1. Our engine starts and runs fine for about an hour. Then suddenly stops. It can be re-started immediately and runs fine for another hour or so. The only thing we have done mechanically is add an electric fuel pump.

My first three guesses are all the same; i.e., the fuel pump you installed probably has too low a pressure rating.

The normal fuel pump pressure for an Atomic 4 powered boat is a nominal 3 psi. Boats (like Catalina 30's), with fuel tanks lower than the engine and 6 to 8 feet away, will need a nominal 4 psi pump. If your tank is high and close, there may be a partial restriction somewhere in the system which your old pump was handling, but the new electric pump cannot. Updated: May 15, 2009