Re: prop pitch
If the 15 is presently the proper pitch, allowing the engine to run at the upper end of the WOT range, adding 4 inches of pitch will lower the rpm by about 800 rpm, resulting in poor holeshot and probably lower top speed. If the 15 is allowing the engine to exceed the recommend RPM then adding the 4 inches will still lower the top rpm, which might or might not bring into the recommended range. Top speed might or might not increase
