My '68 Johnson 40hp water pump won't pump. I've had it to two marinas and neither could figure out what the problem is. The engine runs fine, but gets no water. I'm no mechanic but I figured if the the mechanic I paid couldn't fix it, I might as well give it a look. The impeller has been replaced three times since I got the engine (the last two needlessly). The water pump is put together properly as far I can tell from looking at diagrams. I have no reason to believe that the guys at the marina would put it together wrong. I removed the lower end and rigged up power to the drive shaft. I placed the lower unit in a tank at operating depth and cranked up the drive. Nothing. With the drive shaft cranking I lowered the unit into the tank. The pump started to send a relatively steady stream of water out the starboard copper tube when the water level reached the pump housing. It seems to me the pump can push the water just fine, but can't draw it up to the housing. I checked the connections on the feeder tube and they appear to be sealed tight. I don't think the problem is there. There is a little hole in the housing opposite the tubes that was blowing bubbles when the water level got to it (after the pump started pushing water), I don't have any idea if it is supposed to or not. If not, does anyone know if a bad shaft seal could cause this? I'm at a loss as to what to try next.
