sarge,

I will assume this is a new TT .42 GP or at least a air bleed carb. If it is not, forget the following: First Be sure to break the engine in with 3 or 4 tanks. I wont go into that as there is many ways to do that. Search the forums for some great expert advise. Then, adjust the high end needle 3 or 4 clicks of the highest RPM. Next go to the idle tuning.

Without knowing what the engine sounds like when it goes to idle, I'd have to guess. I'd check the air bleed hole in the front and see if the idle screw is blocking 1/2 of the hole. That will be a good starting point. Assuming you have set the high end to full RPMS and backed off 3 or 4 clicks, and you still cant get it to idle start turning the idle air bleed screw out to lean about 1/8 at at time. That will be leaning the mixture. If it is getting better, you will be going in the right direction. If not set back to 1/2 and start turning it in 1/8 turn at a time. Then when you get it close, you'll have to go back to the high end and retune that. Then back to the low end for fine adjustment. You should be good to go.

ABC engines are great. They are no worse than a ring engine. Sounds like the guys at the field are from the old ring school. Or jellous of you purchase. Soon you will be flying rings around them and grining.