Water Pump Problem?

I'm trying to solve a mystery on a Volvo Penta that has stumped a lot of folks. Every once in a while, we can't get the sea water flowing through the engine. The engine and water pump seem to work fine until we go and and do a good bit of hard sailing (lots of tacks back and forth, heeling over, etc). After a good day of sailing, we start the engine up and no water is flowing through the system. If we rev the engine up a good bit, turn it off, etc, it will usually start "spitting" again.

The impeller has been replaced several times as well as the heat exchanger. Hoses have been replaced and the system has been examined for potential clogs (none can be found). Engine is meticulous otherwise.

Any thoughts or recommendations of places to look? Should the water pump be replaced? Other ideas?

Hi, most likely a worn shaft seal in the pump.

Charlie w.

Close the sea-cock before you sail and heal the boat over.

Your water pick up is probably to high on the hull and when you heal over you introduce air into the system.