How it works: 150cc GY6 Automatic Choke


We frequently receive questions about how the auto-choke and its operating needle work.  It’s a convenience that gets a bad rap from those desiring the control of a manual choke.  To the auto choke’s credit, usually problems starting and running on a GY6 engine are related to dirty carburetor jets, but the auto choke system can be to blame sometimes as well.

If you’re in need of an auto choke or resistor, we take a look at our GY6 Electric Parts and other related components.  They come with warranty, of course!

A case of identity confusion

As it turns out, the auto-choke isn’t a choke at all.  That is, it doesn’t choke airflow through the carburetor like you would find on a lawnmower or generator type of engine. Instead, it sends extra fuel through the carburetor. This is called an enrichment circuit.

It's not a choke after all!

It’s not a choke after all!

The Choke Regulator Resistor


The magic Choke Resistor.

The function of the choke resistor is to make sure that your choke doesn’t get hit with a deadly dose of over-voltage at high engine RPMs.  If this resister goes bad, the choke will likely become damaged shortly thereafter.

How it all works

This circuit is controlled by the charging system. When your engine is off, the choke (enrichment circuit) is actually “on” in it’s default resting state. When the engine is turned on and voltage is applied to the choke, the needle extends and eventually plugs the enrichment ports within the carburetor. This happens within a couple of minutes as the engine warms up.

Testing your Auto Choke

What we usually see with a bad auto-choke is that the engine will start up and run great cold, but as the engine warms up there will be problems driving, starting, and/or idling.

Test Procedure

  1. Remove choke assembly from the choke holder on the side of the carburetor. The needle should be clearly visible.
  2. Measure the overall length of the choke from end-to-end, including the very tip of the needle.
  3. Now connect the choke’s electrical leads to a 12v power source. Black is negative.
  4. Wait 5-10 minutes and re-measure. The needle should have extended.
  5. The overall length should be approximately 3mm more than before.

15 thoughts on “How it works: 150cc GY6 Automatic Choke

  1. Don Rankin

    How do I remove the choke on the 150. Looks like you just pull it off. I don’t see any fasteners. Thanks, Don

    • Buggy Depot Buggy Depot

      There is a golden-colored clip holding the choke in place. You’ll need to remove the two Phillips-head screws holding the clip in place, then you’ll be able to pull the choke right out with minimal force.

  2. Batha Nyathi

    Hi, why would you need to take/pull/disconnect your choke, is it not on the scooter for a reason?

    so my scooter won’t start with just my start and front break, like I normally start it, had to kick start it, took it to my dealer, who said I needed to disconnect my choker. I don’t understand that, surely there must be a greater problem than just pulling or disconnecting something? oh I had just taken in my scooter for a service three days later I had this problem

  3. Brandon

    My buggy starts fine and runs fine at idle, but boggs down and will eventually die under any heavy throttle or load. I can do about 10 mph on flat concrete. I cleaned the carbuerator and it still does the same thing. I even unplugged the auto-choke and it still did the same thing. Any thoughts? I already ordered a new resistor so once that gets here I will see if it fixes it.

  4. mike

    I took mind off my scooter it seems to work better
    it just has a little problem warming up butt that1s okay
    and i`m getting better gas mileage !

  5. Brandon

    I installed the new resistor and it still does the same thing. While working on it today, I was installing some new front lights and a rear running light; the stock ones didn’t work when I got it. I realized I have a bigger electrical problem. When I hooked up the rear tail light, the light would light up really bright and within a few minutes it blew. This happened to three different bulbs. Anybody have any ideas?

    • Brandon

      I installed a new voltage regulator hoping that was the issue. Engine still does the same thing but haven’t tried any new lights to see if they blow.

  6. Woz

    I’ve got the same problem as Brandon, the GY6 150cc engine will idle run up to the higher revs then start running like it’s starving. I have cleaned the carby 4 times, replaced the secondary coil, CDI unit, flushed fuel lines, checked for damages hoses & wiring, change the spark plug & gapped it, removed & checked the operation of the choke, I’m lost on what to do next. I’m in need of help!! Xmas is coming & the kids want the buggy on the track!!

    • Bryan

      Woz – I have the identical situation as you – with Christmas only 7 days away now! :(.

    • Robert Kosaski

      Have you tried to clean the tank filter / inline tank tube. I was having similar trouble where I could see the fuel fill the inline filter, then as the engine rev’d it would drain the fuel and empty the filter. I have taken it out of the tank and cleaned it and blew it out with compressed air and seem to correct my issue. Thanks to BD for allowing all of us to help each other trouble shoot and buy the right parts.

      • Ned

        Sounds like yall need to clean carb. Drain the fuel too, if there was any old in there. Change the filters as well. Idling good and bogs down under throttle, means not enough fuel. I would try the fuel filter first and go from there. Also check your vacuum lines for the fuel pump. If they are cracked, might be keeping the pump from working optimally.

  7. jae

    Hello and how are you all I have a Helix 150cc -can the auto choke
    be by passed

  8. Jody Johnson

    I have the same problem, been broke for two years. Runs and stalls. Brand new card, plug, hoses, filter, petcok, gas cap. Thing is driving me nuts.

  9. Chris

    I have a 150cc crossfire and was having the same problem. It would start fine, idles normal, and drive off as it should… but under full throttle it would bog down and act like it was flooding.

    I replaced the CDI, Coil, Spark Plug, Carberatur, intake manifold, Air filter, and Fuel filter. After all of that the buggy still bogged down exactly the same as before.

    I finally took the entire air box assembly and filter & all hoses off including the vacuum lines and she now runs like a bat out of hell. Full power and not bogging down at all.

    As soon as I put the air box back on it bogs down again. The problem must me in the vacuum lines but I cant seem to figure it out.

    For the mean time it runs great without all that hooked up. Any suggestions would be great!

    • Mike

      I have the opposite issue. We live in a colder climate and I can never get the cart to start without a dose of ether. I have replaced the carb and choke, installed the higher performance CDI set, replaced the spark plug and use premium gasoline in the cart. I also have the UNI intact filter. Once the cart is running, it works great, good power, good top end speed and idels smooth. It is just very hard to start. Any suggestions?

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