I bought a new rubber water pump rotor (reproduction) and the engine is still overheating! I checked each end if the water tube for obstructions. There were none. I put a vacuum on the water pick up tube and it held, so the tube isn't leaking. I removed the head and checked the water jacket for obstructions and all was clear. I installed the exact spark plugs per the old outboard book just in case the plugs I was using were too hot for the engine.
I removed the spark plugs and the drain plug at the base of the power head, then spun the engine with an electric drill with the engine in a water tank. At high speed, the water just dribbled out of the drain. I read somewhere that someone got theirs to shoot water about 5 feet with the drain plug removed and the engine running fast for just a moment.
I thought maybe my rubber rotor didn't fit tight enough so I soaked it overnight in mineral oil. No change. There is a very small gap between the rotor and the cam that spins within it. I read somewhere that it should fit tightly on the cam. Could that be the problem?
Does anyone have a close up picture of what the bottom end of the water pick up tube should look like? I think mine may have been slightly altered wrt the black rubber fitting.
I'm about to give up!