My engine runs good flying inverted. If I do a hard outside loop my engine will stall. If I do 2 in a row it will sometimes die. I can do all the inside loops I want and there is no change in how the engine runs. I thought it might be a clunk line problem at first, but it will do the same thing if the tank is full. My clunk line doesn't touch the back of the tank. It sounds like it is running rich or loading up when I exit an outside loop and give it throttle. The tank sits a little below the carb. The engine is side mounted. Hard turns do not cause this.
The engine is an irvine 53.