One possibility is that if you throttle up quickly your accelerator
pump could enrichen the mixture a little too muck since the carb is
also adding more feul and air. What happens if you throttle up at a
little more than a snails pace? If it works better going slowly this
may be the problem.

I know I haven't explained it well cuz I'm tired, but let us know how
a very slow advance works out. In my plane I don't have this happen
if I go slowly, otherwise it sounds as you describe.


No rate of advance necessary. Just hold it steady anywhere from 1000 to 1700
RPM and it is very rough for as long as you stay there.

Jim