Why, it is 4 stroking. As long as your idle and top end are correct, there isn't a whole lot you can do with the midrange without changing the carb or the timing curve.

The only thing you could do with the timing curve is have it where you have to run faster before it advances fully. And you can't do much with that either.

As long as it don't quit, does it have to run perfect all the time?

Two cycles are bad about four cycling when they are not loaded very heavy. Apparently the motor makes a lot of power at this rpm for the prop load that is on it? The only thing that retarding the timing at mid range would do is to have it make less power to where it is puilling harder.

Enjoy,

Jim