raw water pump v. engine water pump v thermostat v ???

[shag]

I would replace the impeller and thermostat anyway. I bet that will correct your problem....

[ers906]

Thank you all, the rubber was partially stripped from the metal housing. I could rotate the water pump and the impeller would turn at low speeds, but at higher speeds/rpms the metal would spin but the rubber part of the impeller was not. Replaced the impeller, some hoses that looked like they may be a problem in the future, checked the down stream hoses for previous impeller parts, and replaced the thermostat. Want the boat to work just as well for the new owner (if I decide to sell) as it has for me the last four years. Thanks again for all of the help to PN forum