Originally Posted by glolar

All,

I am running the GRP modified, and it runs great, but after revving and returning to idle, the idle starts increasing steadily, and keeps increasing until it is very high. Revving the engine about half throttle calms the idle down again briefly, but then it starts rising again.

I have tried tuning both needles (both ways) and the same with the idle screw, and cannot get rid of this problem. Richening the low end seems to work the best, but then the low end is too rich. (Note I always warm up the engine before trying to adjust any of the needles).

Any help is appreciated.

Thank you in advance.