I have reinstalled what my friend calls the “SteamPunk” water pump after reconditioning it.
I ran the motor for about 20 minutes at all RPMs in forward and reverse keeping an eye on the temp gauge the whole time. (simple auto gauge) The temp never moved over 135f, thought the gauge was faulty. When I shut down the engine and it sat for a few minutes the gauge Jumped to 160f and slowly came down?
I had a good flow of water out the pipe the entire time… does this seem normal for the Sabb?
Been years since I’ve played with sea water cooled engines but I remember it was important for them to run very cool because of salt deposits. Modern diesels use heat exchangers so they can run at high temps for efficiency and emissions.
You are wise to look at ways to protect the cooling system on your Sabb. I remember that this was what caused old raw water cooled engines like Atomic 4’s to die. The cooling passages would clog up and the blocks would rust and leak. Anything you can do to keep the corrosion down will extend the life of your very cool engine.
Where do you have the temperature sender mounted? On Calypso, I mounted it on the head of the engine. I don’t recall seeing spikes after shutdown - but we typically turned off all the engine electrics after stopping the engine too. I wonder if you might be having water drain from the head after shutdown - and then you’re measuring hot water vapor.
My sender is in the head, same as yours. It is non-electric I think its called a catheter/ maniacal.
I saw the dock master today he said its common and not a big deal… I hope?
Great engine! Did you reduce throttle for a good period before shutting off? I’m of the mind that they need to be run in the recommended range to avoid carbon buildup in the heat exchanger. The scaling can be reduced by flushing with fresh water. Have a Y-valve just after the strainer. It will also prolong the engine zinc. Or flush at end of season with descaling agent.