Join Date: Jan 2007
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Not sure about the 2QM, but on my 2GM, it is possible to turn over the cover plate, on the raw water pump, if it is scored.
I had the same trouble as you, it would only overheat after sailing / heeling. Never did it at the / from dock. It was losing it's prime, as has been, mentioned. I also noticed more water flow after turning the cover plate over. Of course, if the backplate is worn badly, it still may not be enough.
You could also buy a speedseal, if your cover is worn as well. At about $500, a new pump would not be my 1st try.
Before fixing, I was had to close the raw water seacock when sailing, to keep the prime, and then open before starting the engine. This did work, but I didn't like having to do it each time.
When mine did start to overheat, I was often able to "correct" it by closing the seacock for 10 seconds, to build some suction, or quickly pulling off the raw water to exhaust elbow hose, and revving the engine a couple of times.
Best of luck.. Check that cover closely for scoring. I used an RTV silicon (automotive type) instead of paper gasket, and it works well.