Greetings 4-stroke gurus,
I am having a problem with a Thunder Tiger S54 4-stroke engine. The engine runs fine on the ground, taking off, level flight, inverted flight, even during rolls. The problem comes when in a high G situation like flying level then entering a loop. The engine dies immediately. [&o] Pulling the plane up to vertical slowly seems to have no affect and continues to pull the plane up. I have relocated the engine to a level where the center line of the carb is just below the top of the tank. There are no leaks in the tank or associated tubing. The tank sets within 1 1/2" of the back of the engine. I run 10% powermaster fuel and run an 11 x 7 prop. I have replace the needle valve "O" ring and checked the valve settings. I can find no detectable air leaks. Does ANYONE have a clue as to what my problem might be?

Sonnytex