Had a similar problem on my old freestyle Rush. Tank was too high and kept floodin the engine. Not even a four stroke plug and leaning the thing out helped. Had to get a onboard glow going on it to keep the plug warm. Funny enough when you kept the glow driver thingy on it and the engine at half throttle untill right before take off the engine kept running in the air. Very funny thing to be honest. [:'(]