I went to fly my GP Ultimate today and once in the air, the engine wouldn't run with a darn, a lot of missing in mid range. The problem turned out to be dirt in the inlet screen of the carb, runs fine again. The screen hasn't been cleaned since I bought the engine almost two years ago. The point for mentioning this is the rest of you should clean that screen frequently since I've had the problem on other engines. There are two filters in my fuel can, but fine particles still accumulate over time.

Chuck