More follow up on the evolution .52 heli engine.
After gathering as much information as possible on the evolution .52, I decided to totally disassemble carb and crank case and compare it to my .52 air engine. This is what I found.
The carb is exactly the same as the air engine. Disassembling the throttle extension reveiled that the low speed needle adjustment is no more than an "extention rod" contained in an aluminum housing.
The engine is simply a ringed version of the .52 airplane engine with a larger head.
There for, the engine will not tune with a rich mixture for mid to high end torque.
I have tried it with 15% and 30% fuel.
The result is an Un-tunable engine for helicopter use.
Putting divots in the earth the hard way!