If you haven't checked it as yet, it is possible that the fuel line on the fuel pickup tube in the fuel tank has either slipped off, or it has a hole in it. It is also possible that the weighted pickup tip on the end of the fuel line in the tank has slipped off.

If this is not the problem, tell me if the engine was running okay during previous flights and if this behavior of quitting is recent.

Check that the engine's backplate is tight and that all of the carb mounting screws are tight. An airleak can cause similar symptoms.

Ed Cregger