My 5.0 BGA Onan has an aftermarket fuel pump. When it runs for more than a few minutes it seems to flood the carburetor and the engine dies. Carb rebuild kits are no longer available. When I clamp the hose between the pump and carb to restrict the fuel I can get it to run ok. Before I buy a new carb, could the fuel pump be too strong or does the carb float seat need to be replaced? I purchased it used. We use it around the farm. Thanks in advance for advice!