Would a faulty reed valve affect high RPM? Mine does fine at idle, and doesn't hesitate increasing RPM, but holds at 4200, and will not go any faster. I've checked compression- all three are equal (albeit low at 105psi, but that could be the gauge). Timing is dead-on, I've rebuilt the fuel pump, and the carbs. Changing the prop from a 21p to a 17p increased 200rpm, but no more. The motor is a 1989 Force 85hp.
