Interesting that you would have a hard time with the Evolution engines. I have a few and the first one was a 45 trainer system that I picked up as a lark to see what they were like when they were first introduced. It was put on a friends 3d model and has used 30% Cool Power heli fuel[as he refuses to carry more then one fuel and he flies helis predominately.]
That was over 3 years ago and to this day it is still a one flip starter with a consistantly low idle and a very precise throttle. No bearings have worn out and the prop is an APC 12.25X3.75.Plug is an Enya#3 HOT .
As others have pointed out the needle valve limiter was quickly discarded but that was the only'tweakin' done to it.
I've just started using the 36 and can only repeat the comments that I've made above.
Dennis