How it works: 150cc GY6 Automatic Choke

 
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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

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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.

7 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

      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.

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