Help w carburetor. By indyrider (Read 469 times)

[indyrider]

I have a 150cc gy6 that was running and idling good. I decided to try bumping jet sizes. I went from a #105 to a #108 just to see if I got any improvement. What I ended up with was no idle.

Starts up fine, runs fine if you keep it revved up. Engine dies when I get to idle.


I was able to turn up the idle speed screw about 4 turns and get it to idle but I think that's just opening the carb enough to start on the high speed jet. With the idle speed turned up like that, the air mix screw has little effect, in fact it idles best with air mix screw all the way in. I can get about a 2000 rpm idle like this but it is uneven.

I went back to my original setup and no luck. It still wont idle unless idle speed screw is adjusted way up. And then poor uneven idle and seems to run best with air screw all the way in.

I checked everything I an think of. Idle jet is clean and I ran a wire through it. Idle passages are open I got carb cleaner to flow through no problems. I've checked for air leaks, vacuum leaks and can't find a problem. I must be missing something??  Any Ideas?? Thanks

[tvnacman]

Check the intake manifold for cracks.

John

[indyrider]

OK, thanks. I did end up with a #115 jet. The needle valve has 3 slots and I am in the top, most rich slot.

I got the idle just acceptable once the engine is warmed up, still will not idle cold.

I do want to try the needle valve in the center position but family/work means I need to take a break in the scooter tuning and ride it like it is for a week or so.

Once I get the carb in good tune I'm hoping the idle will come, then again if I did miss an air leak I'm wasting time tuning the carb. The Fun never ends I guess.