The 10GX uses such a small amount of fuel and the vibration of the tank will wet the supplied felt clunk that I doubt that the tank is the problem to engine dying on down lines because of fuel starvation. Is it possible that that the engine is being flooded? The gas carb on the 10GX has does not have a pump but it does have a regulator so it may be that the regulator is not functioning properly due to a contaminate or other problem.

This can likely be confirmed by filling the tank full and shortly after starting, pointing the nose down while holding the plane. It should not starve for fuel with a full tank. If it breaks into four stroking and then dies... it is likely flooding, if on the other hand the RPM's increase and it screams and dies... it would be dying too lean.