Adjusting 212cc carburetors

[Kyle_]

I have a question about the carb on my 212cc motor. I know the idle adjustment screw and the main carb jet but was wondering what the small brass colored screw with a spring on it, closer to the motor It it another jet or something?

 

[mckutzy]

Lets see a pic, you might have an adjustable carb... some are preset from the factory and not adjustable...

 

[Kyle_]

I haven’t posted pictures on here before but if it worked it is the little red arrow pointing at the screw that is on my carb.

 

[mckutzy]

Ahh yes... that would be the idle circuit adjuster.... nice... typically they seal those off after adjusting it at the factory.....EPs regulations and such...

 

[Kyle_]

That’s nice

 

[bob58o]

It is a fuel screw. Turning it in (clockwise) reduces fuel and makes the idle mixture leaner.
Turning it out (counter-clockwise) increases fuel and makes the idle mixture richer.

Be gentle with it. You don't want to damage the tip. Count the turns as you gently turn the screw all the way in so that it seats. When tuned, It should be more than ONE and less than THREE complete turns outs from when it was seated. If the FUEL SCREW is less than one turn out when tuned, try a smaller pilot jet. If the FUEL SCREW is more than three turns out when tuned, try a larger pilot jet.

This is a good video about tuning with the idle mixture screw.
https://www.youtube.com/watch?v=YxpQjDQzX7g