What year? Probably a carburetor issue. Take it apart and clean it. Also, make sure tank is venting ok, and the fuel lines from the tank all the way to the carburetor are all in good shape.
If you have to pump the bulb to keep it running that would be a fuel pump but if you mean you have to choke the engine that would indicate a carb problem.
Both carb rebuild kits and fuel pumps can be had right here at iboats.
