GY6 150cc Ignition Troubleshooting Guide: No Spark?

This guide covers almost any of the 150cc buggies, scooters, or ATV’s with the standard “AC” CDI setup.  The first version was downloaded over 136,494 times and we’re happy that this information continues to help so many people!

Getting started: How it all works

The 150cc GY6 ignition system is fairly easy to troubleshoot in the case of malfunction. There are 4 major components that work together to produce spark, if any of these are defective spark will be lost. What we will be doing here is troubleshooting these ignition parts starting at the source, and working towards the spark plug.

Major Ignition Components

  1. Stator (6th winding and trigger pickup module)
  2. CDI unit
  3. Ignition coil
  4. Spark plug

To diagnose your ignition system, you will need to do each of the steps in this article, in sequence.

Basic GY6 Diagram

Before getting started, take a look at this diagram. Although there are many differences in wiring between models, most GY6 ignition systems work the same as shown in this illustration. You’ll want to come back to this for reference throughout the guide.

Yerf Dog GX150 Wiring Diagram

CDI Pinout Diagram

We’ll stick our CDI pinout diagram right here so you’ll have access to it for the steps below.



A very common cause of no spark is a defective ignition or kill switch. Before beginning to troubleshoot ignition problems, it is best to bypass the switches.

How to bypass your switches

  1. Create a jumper wire from pin #4 directly to a good grounding spot on the engine.
  2. Being very careful not to deform or break the pin, remove the #5 wire from the CDI plug at the harness. This can be done with a sharp narrow tool like an ice pick or stiff paper clip. Looking from the front of the plug, you will see small metal tabs on each pin which secure them to the plug. Push the tab down and the pin will release. Don’t use force here.



Note the wrapped ignition winding, and trigger module

Ignition Winding:
Depending on your stator type, you have either 6, 8, or 11 windings. Of these windings, one is dedicated to supplying the CDI with ignition power. This winding is usually wrapped in white cloth material and sealed over with clear epoxy.

Trigger pickup:
A simple type of crankshaft position sensor. Sends a signal to the CDI to let it know when to send fire to the plug.

Troubleshooting the Stator:

  1. Set your multimeter to read in VOLTS “AC”.
  2. Locate and disconnect the Black/Red and Blue/Yellow wires coming from the stator, where they plug into the main engine harness. (These are both bullet-style connectors)
  3. While cranking the engine, use a multimeter to check for voltage coming from the Red/Black (CDI power wire) and the Blue/Yellow (trigger wire) coming from stator. Place the black lead of multimeter on a metal surface of the engine while using the red lead on the tips of the wires.
  4. There should be between 20vAC ~ 100vAC coming from the CDI power wire (Black/Red), although much lower voltages will still be able to produce spark.
  5. There should be at least 0.05vAC coming from the trigger wire (Blue/Yellow).
  6. Write the voltages down and continue to the next step.

Minimum values:
Stator output: 20vAC minimum
Trigger output: 0.01vAC minimum



Typical GY6 CDI Box

The CDI Unit is powered by the AC current coming from the wrapped stator winding. This current is stored in a capacitor within the CDI unit. When a signal is received by the trigger pickup passing over the flywheel magnet, the CDI will discharge the stored energy into the wires leading to the ignition coil.

Troubleshooting the CDI:

  1. Ensure your multimeter is set to read in VOLTS “AC”.
  2. Just like before: while cranking the engine, use a multimeter to check for voltage at the two primary wires of the ignition coil. Connect your back multimeter lead to the black ground wire at the coil, and with the red lead to the lighter color wire (usually blue or purple, but it varies). At this step we are checking to see exactly what the CDI is outputting. Write the voltages down and continue to the next step.

Minimum values:
CDI output: Can be 5% to 30% less than the output from the stator. The minimum we have seen working is around 18vAC.



Black is neutral, green is input from the CDI

The function of the ignition coil is to multiply the voltage of the power supplied from the CDI, and to send the multiplied power to the spark plug.

Troubleshooting the Ignition Coil:
Check for 0.1 ohm ~ 1.0 ohm across the two primary coil terminals. This isn’t exactly definitive, as we have seen working coils with 0.0ohms resistance. The best way to tell if the coil is bad is to perform steps the steps above. If there is still no spark, the coil is likely bad.



Check for proper plug gap!

The plug is very rarely the cause of no spark on the GY6. If the plug is fouled or cracked it may not spark. Ensure that the spark plug is gapped properly.Recommended spark plug gap: 0.6mm ~ 0.7mm (0.23″ ~ 0.27″)

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193 thoughts on “GY6 150cc Ignition Troubleshooting Guide: No Spark?

  1. Terry "Terry's Small Engine Repair"

    stator :blk/red=53.4 vac. blue/yellow=0.149 vac.

    coil primary wires=0.3 ohms

    cdi to primary wires at coil= 0.00 vac
    have replaced cdi but no change.
    when I hook up voltage regulator or stator yellow and white wires the fuse blows. This quad arrived at my shop blowing fuses as soon as battery hooked up.
    Appreciate any help, way too many hours invested in this job. Thanks, Terry

    • Buggy Depot

      Try taking a look at the CDI power pin (#6). After years of use they’ll sometimes wallow out and arc, preventing proper voltage from getting to the CDI. We have replacement CDI pins and connectors if this ends up being the cause.

      CDI Connection Kit (Pigtail)

      • malik ross

        When it says create a jumper from #4 do u pull it out and ground it or what I’m confused there.

        • Buggy Depot

          Leave the #4 wire in the connector. Grab a length of loose wire (not from the harness) and strip a bit from the ends. Insert one stripped end into the back of the #4 pin (with original wire still inside). Wrap or connect the other end of the wire to a good grounding spot on the engine (bare metal).

      • Frankie

        Got a hammerhead twister gt 150cc. Have no spark. Here’s my pin out.
        1. Input from trigger module
        2. Ignition coil positive
        3. Ground
        4. Open/nothing
        5. Open/nothing
        6. Power supply from kill switch
        I have nothing coming from stator.

    • Buggy Depot

      The fuse blowing problem is most likely related to the regulator rectifier and also likely a separate issue from what is preventing spark. What resistance are you seeing between the the red wire and the others (yellow, then white, then black)?

    • Victor

      Hola Terry.
      Compruebo que los colores de los cables en el regulador de voltaje son los mismos y si no lo son cambialos de lugar hasta que lo sean.

    • Evans

      I have a yerf dog spiderbox no fire to spark plug. I have fire on the wires that hook to the ignition. Put on new ignition coil. Buggy cranked up. Then would not crank again. Checked no fire to spark plug but has fire on wires going to coil. Is something causing coil to go bad.

  2. vetement fitness femme reebok

    It’s the first time when i’ve seen your site. I can gather a lot of hard work has gone in to it. It’s actually good.

  3. Peter Hay

    I am pulling my hair out with a no spark problem. I have replaced the CDI with the better one and motor ran ok for about 4 starts. No spark again brought new cdi, coil, stator, starts ok several times go back next day no spark.
    brought new cdi basic model, regulator ,coil, measured all AC voltages 80v from stator out put, 0.3v from stator trigger, 30v from cdi out to coil. All good at this point, connect the coil no spark and no voltage to coil. Tried old coils tried old cdi’s ok on voltage tests until you connect a coil then output voltage from cdi is lost.
    Re checked the wiring which had not been altered from when it did run to find the earth wire was on pin 3 instead of pin 4 so change this. Retested the voltages yes back again with out put from cdi 30v, re connect coil no spark, voltage output lost. Helpppppppppppppppppppppppp

    • Buggy Depot

      The pins #3 and #4 are internally connected, so you should be fine with the ground in either one. Have you removed pin #5 (Kill Line) from the CDI plug while testing? The #5 pin can complicate testing to it’s best to remove it temporarily.

    • Jr

      Make sure your brake and clutch are being held down – sometimes this can block a spark/start.

    • rob

      Kill switch sticking???

  4. Peter Hay

    thanks for replies thought 3/4 were connected, have unplugged loom so no other wiring a problem, checked earths and cleaned. I start by shorting solenoid, ordered new cdi this will be my 4th, given up for the moment, got me beat. cheers Peter

    • Peter Hay

      Back with a fresh approach today, the Gods are with me. I disconnected the regulator tested all voltages yes there back. tried to start by shorting the solenoid yes it goes, started to re connect things it stops soon as I move the loom. Found the problem. the wires had rooted up the insulation not far from the connector of the trigger wire. Makes sense now as testing with a digital voltmeter little to no current is drawn but soon as I connected the coil and drew current the lead would go open circuit and stay that way until next day when all cooled and probably one hair wire made contact. Cut back the wire, new connectors all wiring re connected runs like a beauty. yes the gods were on my side today, one to put in your dairy. Meggering out the individual wires say on 500v would have shown this and also a good way to check if your earth is good and not corroded, that’s if you have access to a megger or electrician friend. cheers Peter

  5. Nathan

    We have replaced the cdi, stator, pick up, coil,
    And replaced ALL the pin connectors .
    I get correct ac voltage at cdi power, trigger wire, and cdi output.
    But when I hook up the coil there is no longer
    Any output from cdi, and no spark.
    Replaced the cool twice, still same problem
    Replaced cdi with 2nd new one, still same
    Output ac voltage from cdi to coil peaks at 50
    Then drops down. Is it supposed to maintain voltage?
    Why no spark??? Ahhhhhhhh
    Everything is working according to your flow chart, (thank you btw),
    Except no spark.
    Replaced coil.
    Still, nada.

    Thank you.

  6. Larry Rodeheaver

    Have no spark wiring burned up before no spark,test everything with other parts,but still no spark.What could be wrong with it?
    How can I obtain a book for parts?

    • Buggy Depot

      Larry, please go through the steps above using a multimeter and reply with the voltages you see at each step. That will give me the information I need to be able to help.

      For a complete catalog of parts, see our webstore.

  7. James Roden

    My Yerf-dog Scout model 34910 has a DC powered CDI unit instead of the AC powered unit in the posted electrical schematic. Is there a schematic available for the model I have? I also need the expected output voltages for this unit. Thanks, J. Roden

  8. Bob Hill

    Fuse blows. Replaced rectifier. How do you check for shorts?

    • Buggy Depot

      Shorts through the rectifier on these models aren’t very common; the problem is likely a wire connection having unraveled and is now touching a metal surface.

      I need a bit more information to be able to help.

      1. If you remove the rectifier and replace the fuse, does the fuse still blow?
      2. When does the fuse blow? (e.g. when you turn the key, or as soon as the rectifier is connected, etc)

      Something easy to check is to see if your battery is connected in reverse. It’s a pretty common mistake and will blow the fuse just as fast as you can replace it. Admittedly, I’ve reversed the leads more than once before. If this is the case, there will be no permanent damage. Correct the leads and replace the fuse and you should be good to go.

  9. Bill

    Hi I have a no spark on my crossfire 150r so I did your guide on trouble shooting online . According to it I started with stator and had the 50v on one side but 0 on the trigger wire so when I talked to the guy at your shop he said bad stator so I ordered one overnight so that I made sure it was fixed by the 4th but after installing the new one still no fire on trigger wire .I have double checked the switch and the kill switch what …Help
    Thanks Bill

    • Buggy Depot

      Bill, are you using a digital multimeter to test your stator, or is it an analog type (with needle)? I ask because if you are using an analog type, the very small amount of voltage from the trigger wire may not be noticeable. The stator test might appear to be reading 0v, but in reality the trigger module could be fine.

      The reason this is the case is because the trigger wire sends a burst of voltage once per RPM that is only 10ms in duration (10 one-thousandths of a second). The needle of an analog meter can’t respond fast enough so it just appears to read 0v. Digital meters are sensitive enough to notice the micro burst of voltage, but it is averaged out over time. So you end up with a reading of around 0.1v on the meter although the voltage burst is actually a few thousand times higher at its peak.

      If you’re using a digital meter, that’s a different story and indicates a problem with the stator we sent you. Please reply and we’ll go from there.

    • (Mac)

      Make sure that pin 5 on the CDI is not grounded. This is the kill pin. remove the wire from pin 5 on the CDI and see it it will start. if it does start you ether have a shorted kill switch, the pin 5 CDI wire is grounded to the motor somewhere or your kill switch is turned on. Pin 5 should not read any resistance to ground using an ohm meter. If it does it’s shorted to ground somewhere.

  10. gerald

    I have a 150 cc diamo trace. No spark I replace the coil cdi and stator with no difference. The numbers I have using the pin diagram are # 6 6,0v, # 5 6.0v, # 2 .03v, #1 0.v these numbers were before I change out the parts. Now I am getting #6 16v, #5 16v, # 2 0.2v #1 0.0v Please help I don’t know what to do now!!!

    • Buggy Depot

      Your two problem areas seem to be pins 1 and 6. From your numbers, it appears that your original stator was bad. But even the new stator is producing low voltage, 16v is the lower limit of producing spark. Is your battery fully charged? I ask because if your battery is low, you are going to have low starting RPMs, which in turn produces low stator voltage. Try charging your battery overnight on a trickle charger (1 to 1.5 amps) and take another reading.

      Now about the 0v on pin 1, that will prevent your spark for sure. I recommend this:

      1. Read the comment above yours about how the trigger wire/circuit works.
      2. Disconnect the blue/white wire from the stator.
      3. Use your multimeter to take a reading directly from this wire, stator side.
      4. Reply here with your new readings.

    • (Mac)

      I don’t understand where your getting your reading. Are you talking about pins on the CDI or what? If your talking about pins on the CDI you may be using the wrong type CDI. There is an AC type and DC type CDI. If you posstive battery voltage goes to the CDI you need a DC type CDI. It’s a little larger than the AC type.. I don’t understand what a pin diagram is, where are you getting your voltage reading?

  11. James McQuiniff

    I have a Hammerhead Gts 150. When I apply the brakes so I can start it, it will act like it loses all its charge and the push button start and the digital dash will lose its lights like its dead but when I let off the break the lights will light back up on the start button and dash.

    • Buggy Depot

      It sounds as if you have a short in the wiring harness. The switch is fine. Are you familiar with how to use a multimeter? If not, let me know. If so, see below:

      1. Turn your key to the on position.

      2. Check which post and wire of your brake switch has constant 12v with the key ON, this is your power lead.

      3. What we’re really after is the other lead of brake switch, mark it. From here on we’ll be focusing on this marked lead, and ignoring the power lead

      4. Set your multimeter to read resistance (ohms). Check the marked lead for resistance to ground. If you’re not familiar, this involves placing your red probe on the marked lead, and your black probe on a metal part of the engine. The valve cover is best. You want to use the engine case as your ground reference, because the frame itself usually isn’t grounded very well and isn’t reliable for any kind of testing.

      Let me know your resistance number, and we’ll move on to the next step.

  12. Chris

    Hey all… Travis told me to post my results here. Stator seems to test fine. Blue/yellow is .1, black/red is 134vac.
    Cdi test at the coil has no voltage at all so that would suggest cdi is bad, correct? I stopped the tests there since there’s no voltage passing the cdi.
    Also, I get no power on my ignition switch. No headlights, brake lights or anything. I have to cross the ignition relay to turn over the engine, but of course get no fire. Could my ignition switch be bad?

    • Buggy Depot

      Hi Chris,
      You’re right, your stator seems healthy. Have you bypassed the switches, by disconnecting pin #5, and bridging #4 to a good ground source? If so, I agree that it sounds like the CDI is bad.

      • Chris Laymon

        Yes, I did that. Ok, I’ll go ahead and order a new CDI. Thanks!

      • Chris Laymon

        Thanks for the confirmation. Yes, I bypassed the switches and grounded pin 5. What about the ignition switch (key) not working? Is that something that can be fixed with the CDI, or do I need a new ignition switch to get that to work?

        • Buggy Depot

          Thanks Chris. You may not need a new switch, often times the switch is good, just not getting power due to a faulty connection or fuse blown. Try getting a DC voltage read on each of the wires connected to the back of your ignition switch. They’re usually marked with “I, II, III” for 1, 2, and 3. You’ll want to leave the engine off without cranking for this test. Let me know what you get, that info should reveal if the switch is bad or not.

    • (Mac)

      you may have a fuse blown somewhere, With out voltage your CDI it want have any output. It needs 12 volts from the battery to work if you have a DC type CDI. Jumping the start relay only spinning the starter, but you also need voltage to other circuits for it to run. An Electric diagram would help finding a blown fuse.

  13. ryan

    I have a coolsport 250, Im getting fire all the way out the spark plug wire but cant get any spark out of the plug. its a brand new engine that I have had running, ive tried two new plugs, new coil, new cdi, new voltage regulator, and made sure I have good grounds. what can be making my coil fire but not allowing the spark plug to spark?

    • Buggy Depot

      Hi Ryan,
      I’m not familiar with the ignition system on 250cc class buggies. But I may be able to be of some help.

      What is your voltage at the coil primary(the hookup leads on the coil) while cranking?

      Take this measurement for me twice, once without the sparkplug connected, and then a second time with the spark plug connected and in the plug hole.

    • (Mac)

      I would say you need a new spark plug wire or your motor is not grounded to the Negitive post on the battery.

  14. George Fitzgerald

    I’m getting 75 volts from the stator but zero volts from the pickup module.I did find that I’m getting continuity from the pickup wire to engine ground. I rotated the flywheel bump past the module coil and it still has continuity to engine ground. I unbolted the module from the engine block and there’s continuity between the wire and the module base. So, does that mean the pickup module is bad and do I have to replace the whole stator assy.?

    • Buggy Depot

      Continuity is normal through the pickup module. The tab is the ground side of the module. Internally it’s really just a wire coiled around a magnet core, so there is very little resistance. Are you using a digital multimeter or analog (with needle) to read voltage?

      • George Fitzgerald

        I am using a digital multimeter. New stator, cdi,coil,regulator. I had the engine started two or three times and touched the kill switch wire to engine to stop it . However the last time I did this I inadvertently touched the wire to the frame to kill the engine. Haven’t had any spark since. Any ideas on this? Thank you for your help.

        • Buggy Depot

          Although the frame usually isn’t a good ground, killing spark through that way shouldn’t have damaged the ignition system. Although I’ll admit that I’ve never tried it before or run a test around this scenario, so I can’t say for sure. The 0v on the trigger wire does seem to be the problem though.

    • (Mac)

      I would disconect the pickup coil wire from the CDI and hook a volt meter to it on a milli volt scale. Turn the motor over and see if you get any pulsing voltage around .5 to 1 volt. Don’t forget to ground back the pickup coil to the frame. If you do I would try a new CDI.

  15. Kevin

    Hammerhead twister 150. Starts right up but blows main fuse after about 30-60 seconds of run time. Regulator rectifier gets warm/hot to touch in this 30-60 second period. Buggy continues to run once fuse is blown, but lights etc… no longer work.

    • Buggy Depot

      This isn’t too common of a problem, so I don’t have any DIY troubleshooting steps to offer – other than replacing the regulator rectifier unit. If you’d like to send your rectifier in first I’d be glad to test it for you so you’ll know its condition before investing money in parts.

      1. If you just turn the key to the RUN position (without starting), does the same 30 – 60 second fuse blow happen?

      2. What model number and year (if you know) is your Twister Hammerhead? Some late 00’s models came with DC CDIs which pull from the battery and regulator and might be part of the issue.

      • Kevin

        Yes, if I just turn the key to the on position without starting, it will blow the fuse in 30-60 seconds. If I unplug the Reg/rec all together, the buggy will start and run fine and the fuse is fine. As soon as I plug the reg/rec back in, the fuse starts to get warm and will blow.

        I’ve ordered a new reg/rec and it should be here to day. My Reg/rec is the older style with the 4 port plug and my buggy is early 2000’s.

        Thanks a bunch for your help and comments. It is appreciated.

        • (Mac)

          Sounds like you hit the nail on the head. I also think it is a shorted Regulator. Good luck.

  16. Dustin

    Ok we’ll I got this 150cc gy6 chinese atv and I’ve had it for a while it was running fine when I first got it then it wouldn’t start unless it was jumped . It wouldn’t start automatically like it should. So it sat in my garage for about two years and now it won’t start. it turns but no start. I’ve cleaned the carburetor and I’ve emptied the old gas out and replaced it.the spark plug seems to be good. When I plug up the battery it automatically tries to start but won’t I don’t know why this is please help

  17. Dustin

    I’ve been working on my atv since last night and I’ve pretty much taken all the electrical wiring Cdi the battery all apart and put it back together and the same thing when I connect the two ends on the starter solenoid it attempts to start but does not someone help

  18. Gary Simpson

    I followed your troble shoot guide for the no spark problem. Oh I have a Baja 150 with a Howhit motor.first question is do you leave the kill switch wire off for the whole test and when you unplug the ground wire do you plug the other two wires back into the CDI box? Next I ran the test with # 5 wire off and # 4 for the stator readings are blue yellow wire .196v red and black 61.1v. Pluged the # 5 wire in for the CDI frist reading 1.050 unpluged 42.6. Coil test .7 omi. I still don’t have spark HELP

  19. bobbie

    i need help we can not get no spark to our fox helix 150cc we put all new parts and new wire harness and new key switch on it and still no spark from the plug we don’t know nothing else to do we also have a black/red wire from the stator and no were to plug it in to there nothing else i can do for it if you could write me back thank you so much we run out of stuff its could be

  20. Raddish

    Hi Folks, I have a variation of this problem.

    Buggy starts and idles fine. However, above idle, it misses and makes no power.
    Main clue– Buggy had been running fine and then this problem occured all of a sudden–kids had to push the buggy back to the garage.
    Not a fuel or carb issue–took it apart and was whistle clean–sprayed jets out with cleaner anyway. Fresh gas. Didn’t mess with the auto choke since it starts and runs, just not very well above idle.

    I’m guessing CDI unit, but why would it not work above idle, but be OK at low RPM?



    • DAVE


  21. Andrew

    Hi, I just brought home a GY6 powered scooter (velocity mp150-7) with an ignition problem (no spark). It was some one else’s project that they gave up on. They replaced the pick up, the coil and the cdi unit.

    I performed the tests as you outlined.
    The stator ignition coil puts out about 70 VAC.
    The pickup puts out 2.2 VAC.
    Those sound good.
    The coil reading was .003 VAC. That sounds bad.

    One other thing, the first time that I tested the stator ignition coil, it was still connected to the cdi unit, and the VAC reading was much lower, is that normal?

  22. Elton

    Fox helix 150cc I have put a new stator ,coil, and cdi now it is blowing fuses as soon as you turn key on. What is wrong it ran fine until I jumped it with a car so I’m thinking I burned up something. Any recommendations?

  23. shouma

    i have a carter talon 150cc. and i have no spark. seems that is comon on these chineese buggys.
    i replaced the cdi, coil, stator, rectifire, ignition switch. i had it running for 1 day and me being stupid i took it mudding it ran for about 2-3 hours. then it turned off . (present) i have a new stator,coil,spark plug, cdi,rectifire. abd i have no spark. i havent replaced the ignition switch which i think can be the problem. does anyone know how i can test it? it has 3 wires white, gree, and red.

  24. rondsmith50

    I have a tank urban racer de 150 gy6 I notice the stator is bad. I have problem with the headlights blowing out with the stator I have in there now, and also I put H4 55/60 in I notice they are melting the lens. the rear running lights are very dim and the indicator lights are blown. Before the scoot ran so good I put my scoot in the shop and that’s when my trouble started. They cut the coil wire from the wiring harness that go to the cdi, and ran them straight to the cdi. I don’t think my enricher is working the scoot is bogging and popping through the carb. Can you help thank.

  25. Robert kint

    Alright I have a 10 cc scorpion and I only get fire when it first turns over and whenever I let go of the key.I’ve gotten a new cdi but could it still be the cdi?

    • Buggy Depot

      Sounds like a bad starter/ignition switch. The switch passes upwards of 120vAC, so the internal connections become arced over time of cycling on and off. When this happens, it prevents spark. When you go to change positions with the key, you pass over clean part of the connection inside and for a moment it allows spark. Check for continuity along your ignition switch to confirm this.

  26. Marsharo

    Tao Tao AT125-F ATV. I have replaced the CDI on this unit 3 times. it starts and runs for about 10 minutes then dies and i lose all spark. Originally I was told I had a bad ground in the system. Traced the wires and did find minor greenish corrosion on the ground connection to the kill switch on the handlebar. I cleaned this off, used dielectric grease and reconnected. replaced the AC CDI and rode for 5-7 minutes then it died again.

    – Battery is fully charged
    – turns over easily
    – no spark at the plug when grounded against the motor

    i was told the charging system could be doing this. I don’t see that in your troubleshooting. is that a myth?

    I just found this troubleshooting guide and will go through it step by step this weekend. but wanted to get some feedback if any of the steps are avoidable due to the symptoms.

    • Marsharo

      Please respond!

      Stator checks… CDI power appears to be okay. No reading on trigger. Although, my stator wire bundle is 100% within a block – I have no bullet style plugs. Also, I have no blue/yellow wire. I have blue/white or solid yellow. When i opened up the case, despite the seal, the timing chain showed signs of corrosion. is the stator capable of getting wet? If I replace the CDI it runs for about 7-10 minutes. is it fried or only more sensitive to lower voltages?

      This entire problem began 15 minutes after my son washed his ATV.

      • Buggy Depot

        Hi Marsharo,
        The charging and ignition systems are separate, although I have seen some cases of a bad rectifier inexplicably preventing spark. To eliminate this as a possibility, disconnect the rectifier.

        Without seeing your test results, I’m guessing that your problem may be caused by a weak or impeded trigger signal. Weak trigger has been shown to cause a heat buildup inside of the CDI. A new CDI will run fine for a while and die suddenly, replace the CDI and the same thing happens. Usually leaves a pea-sized bump mark in the back of the CDI casing where the internal capacitor is located.

        • Marsharo

          Thanks for the reply. The only test results I can give you off the stator; I am not sure i trust but…
          CDI power 12-15v fluctuates
          Trigger – I can’t get any readings. I have tried multiple wires in the bundle but no luck.

          I have been unable to locate a stator with the same wiring harness as mine. I have attached a picture.

  27. auston

    I have a 150cc dune buggie when I try to start it it turns over but doesn’t start what is the problem

    • Buggy Depot

      Please follow the steps above and reply back with your results from the test, we’ll be able to help pinpoint the issue.

  28. blair

    I NEED HELP!! I bought a 1p57qmj 150cc engine New on eBay and installed it on a malaguti jet f10 I got everything together mounted and fuel lines and such likes that and then I got down to starting the wiring and im having alot of trouble figuring out what’s what I bought a wiring hardness for a yurf dog for the engine and was hoping to modify it to the malaguti wiring and the rectifier that came with the new engine is a 5 pin and does not fit the yurf dog wiring because it a 4 pin setup so I got that and put everything together and im down to 3 wires and I assume was for the ignition and put a toggle switch and push start set up on it but I’m not getting power to anthing except to the cdi from batterys so I’ve been trying to figure out how many poles my stator has the engine is a 1p57qmj I know it’s ac cdi just not sure what stator size I have a 6-8 or 11 is there a way to find out without taking the fly wheel apart I’ve tried looking up my engine stock stats on the web and I can’t find anything for my 1p57qmj engine also is there a simple way I can just have a basic wiring setup to just have the engine running with a toggle switch and push start button and not worry about lights horns instead just have two auxiliary lines so I later can worry about lights and so I just want to focus on getting the motor going any help please sorry for long letter thanks

    • Buggy Depot

      1. Which wires are left over? If you could upload pictures of your progress that would help.

      2. Try contacting the seller of your engine to see which type of stator came with that engine, hopefully they will be able to tell you. If not, reply back here and I’ll help work out which version you have.

      3. The ignition system should all plug in for your scooter without having to modify anything. Plug in the stator, CDI, ignition coil, solenoid, and starter switch and you should be able to start the engine. Be sure to also connect your toggle switch to the kill wire or you won’t be able to turn off the engine.

      • blair

        No the wires are all different my malaguti f10 had a 50cc minerali engine it’s an italian scooter and the motor died so I wanted to upgrade and swap engine with the 150cc China engine and the seller on eBay that sold me the motor doesn’t have any idea about anything he’s selling he’s just sells them kinda stupid if you ask me how can you expect to do business if you don’t know your own product well anyways since I’m doing this swap the wires are all different so that’s why I had to buy a turf dog wiring harness I think I might not have the full wiring harness because I got the rectifier,cdi,engine,ignition coil,starter, and starter solenoid all connected and have on one end 3 wires that’s has female plug on it and in the middle I have two wire separated that have plugs on it like you see on the back of a speaker so I figured that the speaker plugs were for the horn or something like that and the 3 wire plug I figured was where the ignition switch goes so I splice those wire and connect them to a toggle switch and push start button I did all this setup based on several similar wiring diagrams I’m posting this on a kindle fire I don’t have a computer but I’ll see if I can find away to upload some pictures soon let me know if you need more info thanks

  29. Blair

    I’m sure I have everything connected right except for the purple and black wires and those three wires I thought might be for ignition so I’m thinking I’m missing something like a whole mother wiring system or something I don’t know lol I’m confusing myself the more I think about it hope these pictures help and that I explained it a little better sorry for the messy wires didn’t want to organize it till I had it all done hope you can figure it out thanks

  30. Zack

    I recently replaced the Stator CDI and Coil and still no spark. I used the multimeter at the CDI power from Stator and test 6~7V. Triple checked the stator and can’t see an issue. I have a Subaru Robins engine that runs great and I got the same output when I tested it. So assumed this is at least enough to get spark, if not run lights..
    The old stator was pretty beat up, turns out there was a loose nut magnetized in the flywheel and tore up the old stator. The new one is a 6 pole setup just like the previous. Too small? Obviously the 6 pole worked originally before I bought it but then was damaged before I got it. I have nothing hooked up besides the CDI and coil.
    I then checked the CDI to ignition coil positive and get nothing at all. Tried it with the new CDI and the old CDI. Same both. Pulling my hair out.

    • Zack

      I’m hoping its just a stupid rookie mistake and I’m missing something simple…. HELP!
      Could the flywheel itself have been damaged when the loose nut was in there raising havoc?

  31. Terry

    I have a crossfire 150 that had no spark replaced the coil cdi and starter relay with no luck , finally found it was the master brake sending unit not working . connected both wires together and started right away. Having problems with brakes so am waiting to replace brake caliber when it becomes available.

  32. William Humble

    Hi, I’ve got a Twister Hammerhead 150cc. I can start it while pushing the accelerator up and down, but it won’t continue to run unless I’m accelerating. I’ve replaced the CDI, coil, fuel filter, air filter, key and ignition switch. Also taken the bowl off the carburetor and cleaned the jets out. Have also checked fly wheel and stator, still won’t run..

    • Buggy Depot

      William, have you taken a look at your intake inlet? It’s the black boot that connects the carburetor to the engine. Usually when the engine will start but only stays running with manipulation of the throttle, the problem is due to an intake leak. Try checking the inlet boot for any cracks or dry rot. If you see any problems in the rubber it’s likely up for replacement.

  33. Bobby

    Have a hammerhead 150. With cdi plugged up I get no lights horn anything. If I jump it to bypass switches it will crank with key. I’m thinking this means a switch, correct? Shouldn’t that rule out igniton switch? Also tried cdi plugged up and kill switch jumped, no luck.

    • Buggy Depot

      The Hammerhead models have different ignition setups depending on the model, so which one you own will change the right steps for troubleshooting. Do you know which Hammerhead 150cc model do you have? If not, I can help identify it.

      • Bobby

        It is a gts150.

        • Buggy Depot

          Thanks Bobby. Which transmission do you have on your GTS150? I should have mentioned in my first reply: If your GTS150 has the Forward/Reverse transmission (no neutral), it will have the standard AC system. If it has the F/N/R trans with reverse then you have the DC ignition system. Let me know which trans you have and we’ll go from there.

          • Bobby

            F N R. I plan on getting a multi meter this weekend. So any real voltage tests will have to wait until then.

  34. Randy

    I have a 150cc GY6 ATV that is getting 30 VAC to the coil but no spark. Disconnected the kill switch t the CDI. Replaced the coil and the spark plug and still no fire. Am I missing something?

  35. Ernst

    Thank you for the troublshooting guide.

    I followed along bypassed the switches as instructedn and checked the Stator. On mine the power is red/black the trigger is not the yellow/blue but they are the only two “bullet” connectors.
    When cranking the AC volts are between 3 and 13. I believe it did jump to 23 once or so but mostly around 3 to 13 vac.

    Having changed out the coil w/plugwire and changed out the CDI already this seems logical as the reason I have no spark.

    What is the right Stator? I have a GY6 clone the Super-Bee.


  36. Ricky83

    I have a talon 125gx. I have replaced the cdi, coil, plug, stator and still no spark. I have omh all the wires to make sure no shorts. I omh the stator, getting the correct readings. I do however did not get any readings from the cdi box to the coil. but it is a brand new cdi. I do not understand why this is happening. it has drove me crazy and ready to scrap the dang thing. I have the park brake set. I have had someone holding the foot brake. still nothing. any help would be wonderful.

  37. Dustin Wheeler

    I checked my wires from the stator I have 69 volts ac. I move on to step 2 checking CDI but have no voltage at ignition coil. So this means CDI is bad right?

  38. Bruce


  39. Bruce

    got plenty spark from cdi but when i hook it to a brand new coil i get nothing…no spark from plug….no juice from coil wire..whats wrong with this picture ???????????????????????

  40. Ernst

    Hello again.

    Thanks to this guide I found out the Stator was not producing a correct voltage so I ended up replacing the CDI, Coil/Plug wire , spark plug and the Stator.

    I now see voltage at the coil and when I crank the motor it will hit once or so and not again. It seems to hit right when I push the start button. While cranking once or twice it almost started. I get backfire once in a while.
    In my mind, from limited experience with other engines, this seems to be a timing issue however I am not sure since the CDI is the brains.
    I went back and took the flywheel off again and verified I had installed things correctly and checked all the voltages again and they looked good. Around 100VAC at coil. Trigger voltage is 0.10VAC

    Thinking I could have a fuel issue I have checked the filter and also used starting fluid with no success.
    So, could I have a bad CDI? Should I clean the carb? Is there other electrical parts to check?

    I am needing advice on what to do next.

    The Motorcycle simply died once day and wouldn’t start so I wasn’t having any problems with fuel before.


    • Buggy Depot

      Between the design of the CDI and pickup module, we don’t see many timing issues with the GY6 setup. Actually, I can’t recall a single confirmed example of a confirmed problem with ignition timing over the years. In nearly every case of a bad ignition part, spark is just gone or intermittent (but still in time). I believe you’re on the right track with cleaning the carburetor, especially if it’s been sitting a while.

      Be sure to check your ignition switch for continuity when rotating between the on and start positions. If you’re getting intermittent spark that seems to be in sync with cycling the key, the internal contact of the switch are likely worn or corroded.

      • Ernst

        Okay thanks..

        I am want to avoid taking things apart that don’t need it.
        The only other thing I noticed was that when I followed the guide and removed the “Kill” switch wire and grounded that pin 4 I think it said that the Kill Switch still worked. I wonder if my wiring is not typical and I somehow damaged the new CDI.

        I don’t know. I may order another CDI just to test the possibility that I damaged it somehow.

        As for taking the carb off well that looks scary. I suppose I should get over that.


  41. bill

    Thanks for the info. After I supplied a new ground to the cdi, I got spark. I still dont know why? since I removed it after and it still runs, but your suggestions were well designed and very understandable
    thanks for your help

  42. John

    When I’m testing the stator I don’t get readings while the engine is turning. I only get a reading when the engine makes the first turn or if I just bump the starter. I’m assuming the stator is done. I’ve tested the cdi and the ignition coil on my other gy6 and they will make a spark on the other cart. Any ideas or new stator time?


  43. robert

    the blue and white wire comeing for moter where dose it go to

    • william chapman

      Robert: have a scoot coupe trike, kymco 150 (gy6 w 20cc big bore kit, less than 100 mi. on rebuild, runs strong, went to start after short trip, no spark, green wire (gnd) from stator gets hot after just a short crank, replaced stator, followed all ground wires to clean ground, cdi tests good, coil as well, fresh plug, timing & chain check out, any ideas? (kill switch bypassed also tried) any help much appreciated, Bill C.

    • Buggy Depot

      Robert, that is your trigger pickup wire. It goes to your #1 pin on the CDI.

  44. Neels

    Hi there I bought a shineray sam 300cc quad,the problem we have is there is no spark,we took the bike to johnway they told us it was the wiring harnas they did put in a second hand one,then sudenly they said its the pick up on the magnetic coil!!we replace the pick up but still no spark can someone please help me

    • Buggy Depot

      Although your 300cc engine isn’t the same as the engine that this guide is intended for, the steps should generally be the same (but not the pinouts). Try checking for voltage coming from your trigger pickup, stator voltage, voltage at coil primaries, etc. And reply with your results, we’ll try to help.

  45. Tristann

    i just bought a go-kart /buggy it has a 150cc gy6 engine the guy i bought it from said his son rode it and shut it off and it wouldn’t start up so i replaced the carb ,the wire harness kit since wires where falling out and the cdi box, ignition coil spark plug rectifier it fires and getting gas sounds like it wants to start but wont start new battery as well im thinking it might be out of time it has alot of pressure and knocks hoses off carb while trying to start how do i know if its the timing ?????? any help would be awesome

  46. chris

    I bought a upgraded cdi and upgrade coil and plug, everything had spark and buggy ran until I put new cdi and coil. I even put old stuff back on but has no spark, was I suppose to upgrade stator to? I’m stumped and got a $2000 lawn ornament just sitting. I need help plaease.

  47. Brian cockrell

    I have a tumberlin crossfire 150. I can’t get fire to the spark plug. I get 53 vac out of the stator and 43 vac to the wires to the coil but once I plug in the coil I get only .8 vac therefore not getting spark. I have checked all the wires to to the cdi and from the stator and I see no breaks or frays causing an open or a gnd. Any help would be greatly appreciated. Thank ypu

    • Brian cockrell

      Also the coil has been replaced as well as the spark plug.

    • Robert Kosaski

      I had a similar problem on my Baja Dune 150. (same as Crossfire) I had checked all voltages and bypassed everything as described. I even replaced all the electrical parts hoping for some luck…No Luck. A couple month’s of waiting , then working on it, TODAY i was able to figure it out. It was my KEY SWITCH. I know they mentioned the kill switch and mine was fine. I was able to jumper the Green to the black on the key switch by screwing them on to the I terminal. This will always be hot and you can only turn off engine using the kill rocker switch. I am so exited, this has plaque me for a while. so it sat broke and my kids were bummed because they had to ride the other POS.

      You can trouble shoot the key switch with a multi meter. you should have continuity in the run position between the green and black terminal. Good luck I hope this also solve someone else s problem. Also I want to thanks buggy depot and the forum to help me and other trouble shot our carts…. big thanks.

  48. noah luke

    I am very uneducated when it comes to motors. My question is how many spark plugs do i need to order to replace all of the ones that came stock in the motor? Thank you.

  49. randy johnson

    I just got a 2008 mp150b scooter. It won’t crank at switch But will jump start and kick start. Idles for a few seconds and dies. Changed fuel lines and back lines with new gas. Just don’t have power at switch. When it cranks for few sec,the kill switch will kill it. Know Carb may need rebuilt or replaced. Just the start or any ideals on what to do. Never have had or worked on one. I just don’t won’t to do anything to burn wires or hurt the scooter. The scooter has 14 miles on it and crashed. Didn’t hurt bike But never been road sence. My name is Randy and I need help. Thanks

  50. Carl

    I have what I believe is a Hammerhead 150 with F/R and twin chain.

    Was all working fine when I got it then the starter clutch destroyed itself. Fitted a new clutch, engines turn fine now but wouldn’t start.

    Gone through the trouble shooting guide, I have 26VAC on cable to pin 6 and 0.22VAC on cable to pin 1. I have 0 resistance to ground on cable to pin 4 and I have proved that the ignition takes the cable to pin 5 open circuit and back to ground(also checked this didn’t change during cranking). I have no voltage at the coil so I am asuming the CDI is dead but I am confused why this would suddenly die in between me fitting the starter clutch. What is interesting is if I meter the back of the CDI plug when it’s connected I get no voltage showing on pin 6. Again I guess this points to the CDI. Are they a common failure? I’m concerned I’ve missed something. A new CDI and coil only cost less than £15 so I will order them.


  51. Timmy Matin

    I have a mdi 150 cyclone it runs with key on crank let go and shuts off

  52. Kenneth Abraham Lakale

    This is a good site where people get help and help others. Share ideas. Very good.


  53. Tim

    A friend got a Diamo Velocity 150 that refuses to fire. We are tearing into it trying to locate the problem. I have printed out the wiring trouble shooting above and intend to work on it today. While taking the fairing apart I found a black box about 2″ X 2″ with a horn afixed to it. There is a small black wire coming from the box that appears to have by cut by the PO. Can you tell me what this box is and will it keep the scooter from firing? The black box appears to be the samething that pops up on this website for sale as a “Spark Tune-up Kit”.

  54. Chris Hodges

    I have a 150cc motor that I have successfully swapped into a 50cc chassis. When I got the engine I floor tested it and I had to replace the pick up. Then it ran , after the swap I rode it a few times. I rode up in to the garage and shut it down. The next time I went to it the battery seemed dead (new battery). So I charged it up. Then no spark. I am a mechanic, but we all get stumped and all data don’t cover gy6 engines. Anyway No Spark. I have good voltages all the way to the coil with the coil unplugged. As soon as I plug the coil in its all lost. Whats up with that ? CDI not producing under load ? Or a BS short somewhere ? Ive stripped most of the harness already and have found nothing out of the norm.

  55. Leon

    Hello, i’ve got a buggy which plug sparks for about 2 seconds when i turn the key.
    Then it just stops sparking. Already swapped the cdi unit and the coil. Can you help me please?

  56. Chris Hodges

    I know this is a buggy site sorry but its a good gy6 site. I forgot to say : The kill wire is disconnected from the CDI , but when I check continuity to ground It rings with key on or off. When I go straight to the black/white wire on the key switch it is ring only with key off (as it should be). Ive traced the wire almost all the way and haven’t found a problem. But with it disconnected from the CDI it doesn’t matter anyway right? BTW before the swap it ran fine.

  57. Daniel

    Ok, I’m ready for some help. 🙂
    Engine won’t start on a MotoBravo Paparazzi. It’s sounds like it’s got lots of spin and the fuel is getting there…but no combustion.
    Starter is New.
    Fuel is entering the carb. Lines are New. Stator replaced and spins.
    Red/blk from stator (New) = 60VAC, blu/ylw = 6.5VAC
    Ignition Coil (New) = 30VAC, 0 ohms (analog). CDI is New
    Spark Plug (New) = gapped to .6mm

    Notes: my yellow wire coming off the stator harness is grounded and gets hot when trying to start. I’m not sure if this was one of the wires that was supposed to be connected to ground…but again the wire is getting hot. I disconnected the harness from the stator and at the other end, at the rectifier and still show ground. So, maybe it’s in the plug??

    • frank

      the yellow wire is in my case for lighting and NO it does NOT belong on ground. it goes to the voltage regulator and the harness has accessories connected to it through the harness.

  58. Dennis Booker

    Great site! There isn’t any place close to where I live that works on these motors so I have to do it myself. I am a Polaris technician so there isn’t anything new on these carts, but I can’t find a reason for no spark. The starter clutch wore out an I replaced it, now no spark. I have .252 vAC at #1 / 29.7 vAC at #6 / direct ground at #3 / full continuity at coil from #2 / 0 vAC at coil. Kill at ignition switch has been bypassed. The #5 is empty. The kill for the engine is by grounding #1 at ignition switch. I’ve tried 3 new cdis and no spark. Below is the vehicle information.
    Can the stator be installed 180 deg out (upside down) cause this? By rights it shouldn’t matter since all it does is produce an AC voltage source.

    Kinroad XT150GK-2 buggy 6 pole a/c stator/cdi

    • frank

      yes it would matter but I don’t think it’s possible because the key way would not be correct and would not allow you to put the stator on. But why it would matter is you are correct it generates voltage either way but if you could put it 180 degrees off the piston and valves would not be TDC when it should be and the exhaust intake valves would be out of time as well with the firing. But I don’t see any way to put it 180 degrees out.

      Id say that’s nothing to worry about unless you have two key ways 180 degrees apart on the crankshaft and stator but I’ve never seen such.

    • Greg

      The stator does not have a key way . The starter clutch and flywheel do though. Did you gets your to spark yet? I think I may have put my stator on upside down

  59. mithereal

    i have a similar issue, i checked the 2 wires that plug into the back of the coil when cranking it and i get pulses from 13~18v
    so i replaced the coil with a stock one thinking that was the issue, nogo. i pulled the plug out and it doesnt have a terminal nut on it, its a ngkcr7hsa i replcaced the stock one around a year ago, and was running fine, i dont remember if it had a terminal nut and if i am having an issue because of this missing, the ngk doesnt seem to want to stay clipped in the boot as i tried to plug the ngk into the boot with the plug out of the motor,

    • frank

      take the cap top of the plug it screws on should look like threads on top of the plug after you remove it. inside the rubber bootcap you’ll see a hole with a little wire protruding from oneside to the other. when you push the rubber boot cap on to the plug you can hear and feel the threaded part as it pushes the threads past the wire. it makes a clicking sound. the plug is installed to the boot cap properly.

  60. Leo St. George

    I have a cg 150cc engine I am installing in a home built buggy. I wired every ting and had no spark. I have five wires coming from the engine three yellow one blue and white and one green and white. The blue and white I assume is the trigger wire and it has 0.05vac The green and white the power to the power to the c.d.i. I assume has less then one volt ac. The three yellow have only 2vac coming from them. This is a brand new out of the crate engine. Did I get an engine with a bad unit? Is there any other test I can perform to pin point the problem? Any information would be grateful.
    Thank you for your time and have a great day.
    Leo St. George

  61. ben sullivan

    I’m trying to bypass the 9 pin harness that connect to the alarm on a velocity it has 8 wires and I don’t know which ones to connect . any help ?

  62. Herb

    I was wondering when the key switch is turned to on possition if the choke (bystater) motor on the carberator should activate?

  63. JP Morgan

    My GY6 has new stator w/pickup, CDI, coil and carburetor. I get spark but it is snap, snap, pause, snap, snap pause. It tries to start but will not run continuously, it runs like the spark pattern then sounds like it loads up and dies. The pick-up sensor shows good voltage. Has anyone seen this problem? Any suggestions?

  64. Casey McRae

    I have a tomberlin crossfire 150cc gy6 clone. I have ac voltage going to coil until I connect the wire to the coil. My green wire coming from my key switch(ignition) ohms out to ground. I have no fire to spark plug. I have changed CDI stator and coil any ideas would be extremely helpful.

    • Casey McRae

      Okay I am pulling my hair out now. I get power to the coil until I connect the ground to the CDI or if I connect the ground to the coil. Any help??? I have replaced everything and did the steps offered still no go.

      • frank

        where or what pin are you putting the ground on ? also where is your ground coming from? I had a problem once thinking my frame was grounded but it wasn’t or not very well at least. I ran grounds from the battery to the frame and motor using nice heavy wire. Solved my ground issue. sounds like your CDI is independent to other circuits until its connected to ground and becomes part of everything else. So make sure the kill switch, key switch, and possibly the brake switch are either out of the circuit, or properly connected and positioned for starting. ie brake applied, trans in neutral etc…. make sure your not using the kill switch of the cdi as ground, that’s for shutting the darn thing off. if that’s the case its working perfectly 🙂

      • frank

        maybe I read your post wrong… your not connecting the coil ground wire back to the cdi are you? I put the coil ground to the engine frame.

      • fire54

        kill switch isent hooked up right or is fulting out.

  65. Chris

    Ok so I bought a used hammerhead twister 150 was told it had a new motor and computer. Since I have had it, it runs like crap Bogs down with just a little trottle and backfires like crazy, thinking it was a fuel issue I went a head and replaced the carb, so it is still doing it so now my thinking is misfiring, is there a way to check/ adjust the timing?

  66. frank

    Frist I have replaced the following parts
    1) Stator
    2) CDI
    3) Regulator
    4) Spark plug
    5) Coil
    Using the wiring Diagram I have made my own plugs and disconnected all other wires. I have the ground from the battery going to the frame and the engine with new wire and connectors and cleaned contact locations. Verified with ohm meter ,01 ohm for ground contacts.

    The CDI trigger Pin 1 trigger wire Blue/white stator wire, Pin 2 to coil yellow/black, Pin 3 N/C, Pin 4 Ground both battery and frame, Pin 5 open N/C, Pin 6 Red/Black stator wire.

    The voltage regulator is not connected DISCONNECTED

    Voltage at the red/black stator wire not connected to CDI is 110 v AC
    Voltage at the Blue/White stator wire not connected to CDI is 300 mv
    New Coil resistance very low less than 1 ohm
    Old Coil resistance same less than 1 ohm

    With the red/blk wire and the Blue/white re- connected to the CDI the measured coil voltage output is 18v AC
    Voltage at COIL is 18v AC when measured across both ( Volte meter leads one to each connector at the same time)
    Why is the voltage so low. Tested with OLD CDI and received the same readings.

    NO Spark at PLUG

    Question does the Voltage regulator have to be connected? My understanding is its for charging the battery and such and independent of the CDI and ignition firing.

    Now before when it did fire I had the stator red/blk wire going into the Voltage regulator on the red wire pin ( normally the red pin is the battery input to the voltage regulator) So I had a Y connection on the red/blk stator wire one to the CDI and the other to the Voltage Regulator but it would spark and run. but the battery would not charge before. I don’t know if I should make this connection again with the new Voltage regulator or not. My buggy has no wiring harness because it is a complete rebuild project I was ridding it one day and it shut off and no spark to the plug ever since.

    So where did I go wrong either now or before ? I totally agree with your wiring diagram! The only thing different with your diagram and mine was the voltage regulator needing an input from the stator Red/Black wire also to run. But again that doesn’t seem right because the voltage regulator and the cdi are to different circuits and it should not effect the CDI if the VR isn’t even hooked up at all.

    I’m lost now don’t know what else to try. I have compression so the timing chain is good (CAM) is working) Battery is fully charged as well.

    • Ron Matthews

      I thought one side of coil should be grounded.

  67. brandon

    hello having no spark problem

    new spark plug and Ignition Coil wire

    from cdi 1 — 0.01 volts
    2 — 4.6 volts
    3 — 0 volts
    4 — 0 volts
    5 — 75.5 volts
    6 — 75.5 volts

    from stator


    65 volts

    0.01 volts

    when i take off the ON on the key it jumps too 2.5 v to 4

  68. travis smith

    I have a diamo torino 150. I have replaced the stator, cdi, startor motor and coil. the spark plug is fine. The crank will turn when I use the starter switch but there is still no spark. Any ideas on what I could be missing?



    • Bill

      Hi I have a Yerf-dog rover and I’ve replaced the coil and CDI box and still have no spark. When I turn the key on I get 1 spark and that’s it. Do you have a suggestions?

  70. scott

    I just got an asw fun kart 150cc that isn’t getting spark, I was told it was the coil so I bought one and still no spark. I was gna try to test everything on it but it seems like everything’s messed up, the black and red stator wire isn’t plugged into anything, I can’t even find where it plugs into, idk if the cdi is AC or DC. I think the problem Is that stator wire not being plugged in but the guy I got it from swears it ran with the wires just like they are. I don’t know too much about these things so Im hoping someone can help me out?

    • DAN

      Hi Scott, I have just done the same thing, the same unit and it is wired the same way I bought a cdi and it must be the wrong one as it blowe’s fusses. the schematics they show are wrong for mine its wired just like you said.

      did you happen to find any answers yet or a relevant schematic?

      • Scott

        Hey Dan,
        I eventually figured out the problem was a bad stator, I changed the stator and left the wires how they was and got spark. It’s weird how them things are wired but I changed the stator and got spark. Good luck on yours!

  71. Kevin

    I have a Twister Hammerhead UM125 II R. It’s been running fine the last few weeks. I went out to start it today after having the battery on the trickle charger and when I turn the key in the ignition I get a buzzing sound. The buzzing comes from what I believe is the starting relay. I’m not sure if this is the problem or just the source of the buzzing. Any ideas? Thanks.

  72. Mary

    Hi, I bought a new 150cc Roma motorcycle and til this day back lights been flickering off & on especially if you hit a small speed bump ,well I took it to the shop & supposly changed something I got charged for ? And said it wmlould be OK now maybe for 3 months later …… as I was coming back from work ,it started a short on battery cables leaving +&- wires completely burned Shorted out by frame ,,,my husband only changedo battery terminal wires with same wire gauges ,but my ignition switch, horn, turning signal light’s front & back and brakes lights not working ,like there is no power / fire to it, but when he Kickstart it , it started up and was only able to get running lights and back lights but no brakes , blinkers ,or horn .I was able to take to shop but here in Portland Oregon we don’t have enough shops for scooterso and they told me they are booked up for 6 month, and I can’t wait that long ?any suggestions for me to do ,please help ,thank you?

  73. Txcorruptor

    I am working on a SunL GY6 150 cc dune buggy.
    Stator is putting out 17 VAC
    Trigger is putting out 0.1 VAC
    I am getting nothing from CDI. I have the old cdi and a new one. I am getting no power from either. I grounded number 4 pin and cut wire on number 5 pin. I got this buggy as it sits. It was supposed to run.

  74. Txcorruptor

    I am working on a SunL 150
    Stator 17 VAC
    Trigger 0.1 VAC
    CDI nothing

    I have two CDI’s and neither one read any voltage. One is brand new and other came on Buggy.

  75. Brent

    I have a yerf dog go kart with a gy6 150cc engine. No spark. Stator has 60v at supply wire, .04v at trigger wire, cdi output is 35v and coil reistance is .05 ohms. When cdi out and ground are connected to coil, output from cdi drops to 1.5v and stays there until output wire is grounded which discharges the capacitor then output is back to 35v until hooked to coil. Everything is disconnected except for the ignition system wires. Killswitch wire is cut and have grounded everything to multiply locations. Need help! Im lost.

  76. fire54

    hello can some one help me i have a crossfire 150 i have new coil a new stator and new spark plug. but yet i dont have any spark? Could this possibly be the CDI box? Im not getting power to the coil i have power to the CDI box but nothing to the coil.

  77. jerry Wimmer

    I have a hammerhead gt 150 with new coil, cdi,and when it cranks the coil fires briefly then quits sparking unless i wiggle key back and forth and starts sparking a little again. it does try to start for a couple seconds. power wire from stator has 30vAC and trigger wire has .1vAC. all voltages check in range

  78. Greg

    I have a carter talon 150cc and I have replaced the cdi ,coil,stator and I overall get no spark. One really odd thing I see that seems like a problem is that the performance cdi I bought has a light on it and when the key is in the off position it lights up and when it is in the on or cranking position the light goes off. So I did a voltage test to see what is lighting it up my green wire going into the cdi has 12 volts with the key off but when you crank the engine or turn the key to the on position there is no voltage at this green wire. I did a continuity beep test at this green wire in the on and crank position It has continuity to ground. Is it just me or should this wire not have 12 volts going to it while the key is off. I would think it would just always be grounded.

  79. will


  80. Rick

    I have a 2006 tank urban touring 150 de . It has less than 4000 miles on it. I got it they lost the key and the alarm box is missing. I followed the test procedures in your post. the CDI is bad. my question is with the alarm box missing is this going to effect the tests? thank you for a great post, it help me alot Rick

  81. aaron

    I been confused I been having problems with my go kart not firing it trust to turn over but won’t fire up it was working good then one day wouldn’t start changed battery cleaned Carb and adjusted it but still no fire the kill switch on the motor was broken off some how could that be the problem I tried to bypass it but still nothing can someone help me out

  82. Kim Sweet

    i have a 150cc GY6 that runs good but starts cutting out and bucking when it gets warmed up and hits about 45-50 mph. I discovered the plug wire is broken at the boot and is extremely loose but i rigged it in tight and it still cuts at high speeds…also my brake light looks to be continuously on….any suggestions for a fix on either or both problems would be greatly appreciated

  83. Kim Sweet

    hey out there…need your help again…put on new pick up coil/spark plug boot….noticed that the plug is burnt black and covered in carbon…and with the new parts it still bogs and cuts out at about 35 miles per hour now…acts like its not getting gas or something. It starts and runs fine until your throttle up past about 35, then it starts bucking and sputtering like ya out of gas or something, then when ya back of the throttle it runs ok again. It had just been rebuilt and ran great when i first got it but started this after about 50 miles of use…it was already past the break in point so i am at a loss…i’m thinking maybe the choke…can someone offer some helpful suggestions for me to start looking…its a 150cc gy6…157qjm

  84. Mike

    I have a 150cc gy6 engine dune buggy. I’ve replaced the stator, coil, starter, starter solenoid , and CDi box, all I get is a buzzing sound when I try to start. Can you help me?

  85. William Klein

    Thank you for the ignition troubleshooting guide. I was able to determine the CDI module on my wife’s Scout CUV was faulty. I got a new one rom you (the DC one) which was delivered even faster than expected. It is now up and running & she is able to drive it to the barn again! Happy wife, happy life!

  86. Corey

    My gy6 does not spark while cranking, but just as I let off the key it fires. It is getting worse, any ideas? Replaced coil, cdi and stator.

  87. greg

    i have a dongfang 50cc df50sst moped and someone cut all my wires from main harness and i need to rewire the whole thing the parts themselves still have a connector on them just got to run main harness to connect everything ign,lights,cdi,starter etc etc does anyone know where to get a harness to complete this and a diagram to follow or how to wire it myself

  88. Evans


    I have a yerf dog spiderbox no fire to spark plug. I have fire on the wires that hook to the ignition. Put on new ignition coil. Buggy cranked up. Then would not crank again. Checked no fire to spark plug but has fire on wires going to coil. Is something causing coil to go bad.

  89. Willy

    These are the list of my problems of my GY6

    1. Spark Plug Fire Is ORANGE
    2. My Electric Start Button DO NOT WORK
    3. I Also Have To Use A SCREW Driver On The Solenoid To Make Engine Turn Over.
    4. When I’m In NEUTRAL And Press The Brake Tail light Doesn’t Light Up .
    5. And I Removed My Kickstart.

  90. Big bill

    Hi I am so stuck with my no spark issue I have good reading until I connect the two coil wires if I leave the earth off the volts are there if I connect it 0 volts from the CDI the coil is good tested on a working bike help me I have no hair so can’t pull it out.

  91. LetsRideBaby

    this is my stator readings black/red wire is 56.0 and blue/yellow start at 00.5 and not even a sec later it drops to 00.2 and holds. does that mean its bad?

  92. Santiago Aguirre

    Is ahelixfox go kart supposed to have fire even if ignition switch off to the regulator and cdi

    • LetsRideBaby

      I would say no if the wiring is the same as above. maybe the key switch is bad. have you tested it?

    • LetsRideBaby

      do you mean your turning the key to off and its still running?

  93. David rice

    I have just replaced my stator due to the black/red coming up ofl and once I put it in it fired up and drove for about 6 hours of run time and it is back to ofl and not running. Why would I keep having this problem?

    • Buggy Depot

      David, I need a bit more information in order to be helpful. Are you testing the Red/Black wire for AC voltage, or Ohms?

  94. Shaun Welsh

    I have some symptoms similar to most of the enquiry above. I need to get some more info but the starter relay chatters as well. Is this a symptom of other issues?? or faulty relay.

    • Buggy Depot

      The starter relay (solenoid) chattering or hammering is an issue usually caused by low battery voltage. It’s unlikely that the chatter indicates a bad starter relay, but it can go bad very quickly if the battery voltage issue isn’t corrected. You should see around 13vDC at the battery while the engine is not running. 12.5v is the absolute minimum.

  95. Arthur Mccormick

    Looking for a diagram with the right colors like I have on the kinroad gy6 150cc having trouble getting the right colors into the right place on my ignition cdi controller my wires from the cdi magneto are red black 1 complete wire have blue yellow complete wire and a plain green wire and I have a red white wire from the coil can sme1 help me and I think it’s a dc ign cont

    • Buggy Depot

      Arthur, all of the Kinroad models I’ve worked with use AC CDI’s. Since you have the red/black wire it’s near certain that it’s an AC setup. Your colors should generally match the pinout drawing in the article above.

      – Blue/Yellow to Pin #1
      – The ignition coil (red/white?) to Pin #2
      – Ground to pin #4
      – Red/Back to Pin #6.

      That leaves the kill wire that goes to pin #5, which you’ll have to trace from the switch in the dash.

      If you need a more complete wiring diagram, our diagram for the Dazon 150 Classic would more closely match your Kinroad:

  96. troy

    I have a kasea engine go kart I bought. Turns over great has great spark and compression. It won’t start. Any ideas??? Please and thank you

  97. James

    I have a crossfire tomberlin 150 got a new switch don’t know where wires go can someone help

  98. Paul

    Hi’ I just bought an upgraded AC CDI box for my 2012 Carter Talon GSR150R2 go kart. This is the Blue racing AC CDI box with a no rev limiter. But here’s the thing.. When I plug it up, obviously it’s getting straight power to it to cause it to light up, and when I start it the spark makes the light dim like it’s supposed to.. But what I want to know is, if it’s of.. Not running, the CDI box light stays on.. Won’t that drain my battery? Is there a way to shut it off with the key?

    • Dave

      It sounds like you have a DC fired CDI. Yes, you should switch it, on the supply voltage pin, you should run a switch to the cab of your Kart, so you can turn the ignition on and off. Forget the kill switch, just cut power to the CDI. If you look at the pinout above, it is pin 6. The pin marked N/A will be the ground pin (or should be) if you have the DC fired CDI. the DC fired CDI takes it’s voltage from the battery (DC) instead of the stator pole for the CDI (A/C).

  99. Bob

    Hello, I have a Baja ATV with no spark. I removed pin 5 (kill switch wire) from the CDI box connector. Still no spark. Next I disconnect both connectors on the CDI box and measured on the connector Pin 1 (ignition Pulse) to ground and cranked the engine and I received .1 VAC. Next I Measured from pin 6 to ground and cranked the engine I measured 55VAC. Based on that information I thought the stator and pick up sensor were OK I re-connected the CDI box and measured the voltage to the coil and received 0 volts. I then added a additional ground wire from the frame to pin 3 still no voltage to the coil. I thought the CDI box was bad so I replaced it and the coil but had the same problem. One thing I did notice was the new CDI box was smaller (about 1/2″ shorter and 1/2″ narrower) The CDI box is a 6 pin rounded type connector.
    Ant suggestions ?

  100. garrell

    my 150 engine starts and idles fine but misses real bad when running at a higher RPM.i have had the carbrator replaced and it is tme same. whats next.

    • Dave

      Have you adjusted your valves lately? Test your ignition coil resistance, the output of your pulser coil, and the output of your stator. Refer to the article above. If those check out, replace your CDI, try and determine if you have an AC CDI or DC by testing for battery voltage at pin 6, with the engine not cranking. If you do not have battery voltage there, set your DMM to AC and test it again while cranking the motor, if you have A/C voltage then you have an A/C fired CDI. My guess is it’s the CDI.

  101. samantha brown

    my dad has a cater talon 150cc dune buggy that has bad wiring. fist we replaced the sator rings worked really good first few days then stop working. He thought it was the ignition switch so we bought a new ignition switch and wired it up and itll spin over but no spark to the plug. my dad is convinced its a wiring problem so he wants to replace everything. Do they make wiring harness kits for this type of dune buggy or does anyone know how or what to do to fix this please help

    • Dave

      Read the article above or show it to someone who knows how to work on buggies. They do make harness kits. It could be the wiring, or it could be the ignition coil, or CDI. If the stator came with the pulser coil.

  102. Frankie Ray

    hello mr Depot lol
    so glad you have your Thread and form here Thank You…..
    I have a 2014 Chinese gy6 150 cc scooter. No Spark.
    Stator Test.
    Stator output. 22.5 v
    Trigger output 0.1

    CDI test. assuming I’m testing correcty. wires disconnected from coil.
    0 v.

    Coil test.
    1.7 ohm
    I also tested the Pinout’s
    pin 1. input from trigger .01
    2 to ignition coil 0
    pin 6. cdi power from stator. 24.0 v.
    am I correct in assuming the Cdi is bad?

    again on behalf of us garage mechanics thank you sir.

    • Buggy Depot

      Your stator output at 22.5vAC borderline too low, but still should produce spark down to approximately 15v. Normal voltage from the stator is normally anywhere between 60v – 120v.

      Trigger output of 0.1v is fine.

      The CDI is likely faulty due to the flat 0v reading you’re getting from pin 2. But I’d be sure to replace the stator at the same time.

  103. Jeredk

    125cc atv. Starts right up and idles great. Revs slightly but as soon as rpms get past about 1500 it dies. It’s an ignition problem and not fuel. If you just tap the start button as its dying it energizes the ignition and it fires again but then continues to die. If you keep tapping the start button you can get it to rev high.

  104. Tom

    What should the voltage coming from the CDI to the coil be? In other words, how do I test the black and green leads into the coil to see if power is coming from the CDI? I have power into the CDI (~85 VAC) and I have tested the coil but no spark. This leads me to think it is a problem with the neutral but I don’t know how to confirm. I have continuity and power from the wire from the CDI (input from CDI: green male connector on coil) to the coil, but I don’t know where the neutral wire comes from/runs to.

    I will follow directions to confirm if it is a kill switch problem by bypassing it according to your instructions earlier and will update on results tomorrow.

    Thank you.

  105. Charles Breese

    Working on a GX 150 Go Cart . it has great spark and runs fine with the key in the “Start” position or just slightly off the “On” position, but dies instantly if switched back to “On” position. I’ve had two switches on it, both with the same results. Any thoughts or comments would be greatly appreciated. Thanks in advance.

  106. Travis

    Hi I recently acquired a crossfire 150r GY6.
    It will not start. Turns over but no fire. It sparked a couple times but not continuous. I ordered the electric tune up kit. I’ve tried the bypass switches and I ordered a new ignition switch. I know the battery is shot. I’ve been using a jump box to turn it over. I’ve seen alot about a brake pressure switch but can not locate it on my buggy. Do the older ones have a switch? Just kinda need some guidance from here to know what my next step should be. Without just throwing parts at it.

  107. Mathew

    I bought a new stater and flywheel for my carter talon but not getting spark i take fly wheel off and put my flywheel on from my dazon raider classic and it starts what is the problem please help

    • Travis @ Buggy Depot

      In order to help, I’ll need your voltage readings. Use the guide above to gather your voltage readings at each step. Post your results and I’ll help you pinpoint the issue.

  108. Cody Brewer

    Question my positive wire on starter is grounded, I can take ignition switch from key and touch it to the frame and motor turns over. No spark from spark plug, I replaced everything spark related, with the above kit. Help please.

    • Travis @ Buggy Depot

      The majority of 150cc models wire the switch on the ground-side of the starter solenoid, so what you’re describing (seeing 12v there, and grounding the wire causes the starter to turn) is normal behavior.

      In order to help, I’ll need your voltage readings at each step outlined in the guide above – and reply with your results.

  109. Tim

    I’m stuck. No power to the coil on my Yerf Dog buggy and can’t figure out why. Followed the steps above (including bypassing switches) and got these results:

    Stator to CDI input: 68v to 71v
    Trigger wire to CDI: .5v to .1v
    CDI Ouput: 0.0v to 2.3v

    Replaced so far: CDI (two times), coil, spark plug, trigger. Swapped back in old parts, still no change. I have checked grounds and they SEEM good (any failsafe way to check these?).

    Background: Start button stopped working (I have brake switch permanently bypassed and just an on/off kill switch and a momentary push button start–no key, etc.). Started jumping solenoid terminals to get it running. Ordered new solenoid and tune up kit. Replaced all. Worked for a few starts. Then stopped firing. No and/or not not enough power to the coil out of the CDI. Can’t figure out why or what else to try. Performed tests noted here and have gotten mix of results. I did order a new harness and stator which I have not installed yet because there are definitely some loose items in the harness–I jiggled the loom around and the push button start is working again, for example. Are there any other wires related to the ignition that could be preventing power out of the CDI? Or is there something else going on here…?

    Thx! Desperate to get this running for my kids please help!



    • Travis @ Buggy Depot

      Tim, your voltages going into the CDI are healthy. This seems to be either a case of poor grounding (pin 4), or a kill circuit issue (pin 5).

      1. Use your multimeter to make sure that you have electrical continuity between pin 4 of the CDI, to any unpainted metal part of the engine. That will resolve any grounding issues.

      2. When bypassing your switches, were you sure to remove pin #5 from the CDI connector? It needs to be disconnected altogether. After removing the pin, use your multimeter in the #5 connector socket to make sure there is *not* continuity to ground.

  110. Rod Bobby

    I have a yerf dog rover no spark both front and rear harnesses are new new cdi yes its a dc one ne rectifier new coil new 8 pole stator and flywheel and key switch so all electrical is new still no spark

  111. Michael

    I just would like to thank you guys for this article it simplifies the entire ignition system. A great how to for a quick look up. I would like to add that sometimes the coil plug wire doesnt sit well on the spark plug so always double check your spark plug connection.

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