I have a .61 and it runs great. However, the HS needle "clicker" (holds the needle steady) loosened up and was letting the needle turn during flight. I removed the HS needle, bent the "clicker" back so it would hold the needle steady and I have had no other trouble. Mine runs great about 1 3/4 to 2 turns out on HS. Low speed arm is set about 2/3 towards rear of plane. I am using Cool Power 15% and the Hangar 9 Super plug.

Great running engine. After you get it set, very little twisting required after that. Maybe just a click or two one way or the other depending on temp, humidity, etc.

Also, to prevent air leaks around the HS needle, I took a pair of forceps and stretched a 1/2" long piece of tygon over the needle and needle housing. Also, helps
reinforce the "clicker."

Good luck