i have a OS91fx two stroke in my bobcat,the only problem is they don't make any pusher prop for that size engine,i had a three blade 14x7 cut down to a 13x7 to clear the booms,i flown the plane we takd at 75mph.could y put a 11x7 on that engine and keep it under 15.000rpm's with out the engine to overheat??????????