I have an old 3 hp seaking with a built in gas tank on top. It gets very hot. I think it might be the water pump. So I took off the prop to get at it and took off two other screws that held on a small plate. What's next. The aluminum spline doesn't slide off. Should I pry it off. How does it come off further. Once I get that off I assume I will have access to the pump. How do I know if it is bad and where can I get parts?