Can't over prime that system. By priming it you just make sure that fuel is to the carb and ready to flow on the first puel, it's does not directly prime fuel into the engine, after the system is full it just recirculates the fuel back to the tank. Sounds like other fuel issues to me just can't put a finger on it. Maybe a restriction not allowing air/ vacuum to move the diaphragm, thus not moving fuel through the carb.