I have the same motor. I have it in my Avistar Trainer. I originally used power master 15% and had a heck of a time trying to get it to idle. I switched to my Heli Fuel Cool Power 15% and it idles and holds at 2700rpm. Yesterday a buddy of mine said to try 20% or even 30% Heli fuel. I tried some of his 20% Cool Power Heli fuel and it held a constant 2500rpm. I have the needles set richer cuz of the higher nitro %. But, if trying different fuel is not an option you can try my setting. The low needle - after you turn it completely clockwise until it stops - I have it turned out 1/4 turn. I think it's still rich but thats where it idles the best for my motor. I don't know what everyone uses but I like Heli fuel thats full synthetic. Less mess and hardly (practically none) any carbon build up inside or outside of the engine.