Idle adjustment doesn't work

[JCW]

I've got a 250 MC 2 stroke that runs great but the idle adjustment on the side of the carb doesn't seem to work. The idle is so low that I have to adjust it at the throttle and that's not a good thing. The bike cranks easy and has great power everywhere, especially off idle. What would keep the idle screw from making any difference from half out to full in?

Thanks,
JCW

[RBD]

Maybe the tip of the plastic idle screw broke off (I have seen this once before).

Ron

[rpduc]

Is it possible to wear a divot in the bottom of the slide where it contacts the screw? I imagine the plastic tip Ron mentions is to prevent that?

The idle screw on my '05 MC 250 is just about all the way in to get a proper idle. The tension spring appears to be fully compressed. I didn't notice that there was a plastic tip on the screw, but I wasn't looking for one when I cleaned the carb.

Could it also be incorrect idle jetting? Ron would be the guy who knows.

[eff]

Originally Posted by rpduc

Is it possible to wear a divot in the bottom of the slide where it contacts the screw? I imagine the plastic tip Ron mentions is to prevent that?

The idle screw on my '05 MC 250 is just about all the way in to get a proper idle. The tension spring appears to be fully compressed. I didn't notice that there was a plastic tip on the screw, but I wasn't looking for one when I cleaned the carb.

Could it also be incorrect idle jetting? Ron would be the guy who knows.

This could be an indication that you are running a PJ that is too lean.

[widebear]

If your pilot jet and corresponding air screw adjustment is out of wack you'll have a hard time setting a proper idle speed

[rpduc]

This could be an indication that you are running a PJ that is too lean.

Thanks eff,
I'll have to pull the jets out of my carb and see where I'm at. The bike seems to run fine, but then again it's been YEARS (30+) since I was last on a 2T dirt bike so my frame of reference is quite cloudy...