Hi Guys,

I've had this trouble the last two times out:

Launch the boat and head out of the harbor and everything seems fine. Once I get up to cruising speed, the water temperature quickly rises to the point where the alarm sounds and I shut down the engine. I then hook up the fresh water hose to the inline Perko Flush Pro attachment on the input side of the raw water pump and start the engine. Temperature quickly drops back to normal. I shut down the engine, disconnect the fresh water hose and start the engine. Boat stays cool the rest of the day.

I've just replaced the raw water impeller about 20 hours ago. Each time I return from a trip I flush the engine with a garden hose using the Perko Flush Pro.

Any ideas what is happening?

I'm thinking either the Perko Flush Pro has got a valve that is sticking or that my thermostats are going bad.

I'm also wondering how the raw water impeller gets primed since it sits above the water line. Is there a lift pump in the stern drive? or is it just pressure from the boat motion?

Thanks in advance,
Terry