Mercruiser Temperature Issue

[beamie]

I assume this is fresh water cooled and not just raw water.

How does it run under load?

Does the raw water first pass thru a oil cooler before going to your heat exchanger? May be plugged up.

Belt isn't slipping?

Did the engine get very overheated at some point and you have head gaskets issues? Eroded impeller on your fresh water side?

There was no blockage of your manifolds in 2001? That was a loooong time ago. Your manifolds are on the raw water side? That is a mistake right there. They should be fresh water cooled with a solid gasket going to the riser.



150-155' seems a bit low operating to me?

I'm not an I/O guy but I assume the Bravo drive sucks raw water up thru the skeg. Is there a plastic piece going from drive, to hose, to into the boat? that may be cracked or loose s#^&#^&#^&#^&#^&g in air with the raw water causing fluctuations.