Thanks for the info. I am running a MAS 11x6 prop on it now. Also Rc Ken you say to run it at top speed and then back it down. Do you mean top speed being top of the rpm range? I understood the rpm range as the max rpm being the lean side and the lower the rpm setting the richer it would be. It sounds like I am wrong, so can anyone tell me what the rpm range is for or what setting the rpm with a tac is good for?