in the current state of the game, you cant get (IIRC) higher rpm in the Spit without enabled CEM !
the propeller is automaticly setting to coarse.......................
Give CEM a try, perhaps let engine overheat disabled if you want. But flying without CEM is without sense in the moment IMHO. And it is BY FAR not as complex as one is thinking , espacially with overheat off
