Cooling System

[phanson24]

So I had by boat out yesterday and at idle its runs a liitle to hot for my liking.

I have replaced the impeller and the maniflolds were replaced before I bought it

And also I replaced the themostat  so I'm thinking the only thing left would be the water

pump it is the original , Also once I get off idle it cools right down 160-180D

Am I right?

Thanks

Paul

[backfoot100]

What a little hot for your liking?

[phanson24]

In the 200-220 degrees range on gauge

[backfoot100]

If it's getting hot at idle and cooling down at speed you have a small leak somewhere in the suction side of the pump. The shear volume of water at speed is overcoming the leak at idle.
This is usually a hose connection on the suction side of the RWP. Make sure all hose connections are good from the thru-hull opening all the way to the RWP with a small socket. Not a screwdriver. Also verify that the gasket on the water strainer is tight. That is also a common place for a small leak. If you can see air bubbles in the strainer while running, it's leaking.

The rear seal on the RWP could also be a possible issue but that would usually be dripping a little bit while running. The seal can be replaced and save the cost of a whole new pump. If it isn't leaking I doubt it's the problem but I was wrong in that assumption once.