Quote from: Ron Hill on July 20, 2023, 02:38:06 PMOh, I see what you mean. However, our lake temp has yet to rise above 6c, so it wouldn't take much flow at all to keep the engine temp down. I'm going to pull the water pump off anyway, to check for that service bulletin collar. It was a cheap part so I preemptively ordered one from Westerbeke and have it here ready to go. They had no record of any contact with the PO, so it may never have been done.
The raw water pump was already eliminated because the temp gage is staying at 160 degrees !!! That also eliminated Ken's dissertation on the water pump's freezing up and breaking the lug connection on the engine (which is VERY important!!).
Will look into all of Ken's suggestions as well, and listen around with the stethoscope.
I've become suspicious of the fuel lift pump. It occurred to me that I had some diesel leaking around it last winter, which I attributed to expansion/contraction of hose clamps and barbs, but perhaps the pump itself is leaking. I could imagine that causing an intermittent hissing, as it fights to maintain pressure. I think it could also cause the bogging of the engine under increased load as we turned up into the wind to raise the sails. Our tank was half full. We have an aftermarket lift pump that the PO had installed at some point after the original failed. Ours has never clicked, it produces more of a buzz. It's always provided sufficient pressure to prime the Racor and bleed the system though.