CATA

I have a MVVS .91 that recently has begun quitting in flight after just a brief time. If I move the throtle to 1/2 the engine runs rough and then quits. There is almost a full tank of fuel left. I replaced the plug, cleaned the carb, took out the fuel system (new) cannot find any problems. I am using 5% fuel, the fuel is good as my ohter planes work fine. I am using 14x6 prop. Max rpm 10200 I richened it to 9400 on the high speed needle. Engine transitions fine on the ground. Anyone have the same problem and how to fix the problem.

Thanks
Charles