If the tank is higher than the fuel needle, and the plane is flying at midair, can the engine stall or something? And why set the throttle at high when you are going to start it? That definately stall the engine because the flow of the fuel into the carb will be many. My idea was set the throttle at full closed position, and then grab the starter. Attach it to the spinner, and when i'm ready, give a little throttle and start trying spin it. If it finally spinning, then i open the carb slowly slowly untill a safe point (with full throttle, the plane is going to fly ). Then, wait untill it starts and vouala. Another idea is to have your plane at inverted position when you are going to start the engine. How about that?