Offshoreonly.com - Mercruiser Overheating (so am I)

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Quote:

Originally Posted by muc (Post 4679121)

No, the bulletin is still relevant. Because it talks about using a clear hose to watch for bubbles and flow.

Install a clear hose per the bulletin and install a second one in place of the hose hose that goes from the thermostat housing to the exhaust elbow, Run the engine and check for bubbles and flow.

That's all ell and good, BUT, like I said "I have now narrowed the problem down to being OUTSIDE the boat (leg). No water coming in the boat. I rigged up a hose direct to the thermo housing inlet from the leg and the engine runs fine, risers warm/cool and engine running at around 165-170 constant."

Thanks to everyone for their suggestions and advice. ! 'm pleased to advise ALL DONE - Unheard of apparently, but the centre part of the impeller was spinning without the rubber blade part turning.Thus no water on the boat. This has been a VERY expensive learning curve, so my advice is never take new parts for granted.