warning horn and light comes on at low rpms but goes off when I increase rpms. Have a good pee stream and engine appears to run fine. Thought it was the water pump so will change that out. Had someone tell me he had a similar problem and it was the fuel bulb loosing pressure??? Sure would be nice if that was all. Any suggestions? Looking to sell this boat quickly. PS - I've never changed the water pump out on an outboard before - how hard is it??? Thanks!!!