1964 Mercury 100hp water pump question

[Number21]

I just bought a boat with a 1964 Mercury 100hp outboard. Runs fantastic, but the pisser wasn't working very good and then water stopped coming out of the exhaust. So, I replaced the water pump impeller and everything is fine again. The impeller I took out wasn't in very bad shape, the fins were a little curled, but none broken off. Why would an impeller like that stop pumping water? I know it's a regular maintenance item, I'm just curious how it stopped working...

 

[CharlieB]

Re: 1964 Mercury 100hp water pump question

Age hardens the rubber and the vanes take on that curved shape will not extend against the pump walls with enough force to seal well.

It is cheap enough insurance to change the impeller at least every couple of years whether it has been run or not.

Many owners replace their impellers religiously every year, just for the peace of mind as added insurance against a cooling problem.

 

[bgc]

Re: 1964 Mercury 100hp water pump question

Every other year is what I do with my Old Mercs....its cheeper than a rebuild and keeps the shaft from rusting to the block....