My Yanmar 21hp is running hot (at least the temperature gauge is showing that it's hot) but I've had everything checked and for all appearances it's running at a normal temperature. Has anyone had trouble with the gauge or the temperature sensors?
Yanmar 21hp 3YM20 Running Hot
- Thread starter Phil4528
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My 3YM20 runs at about 162 deg. constantly. We recently took a one-stop cruise about 45 mi. up Lake MI to South Haven, Motorsailing all the way (about 7 hrs). Engine stayed at the normal temp. Next day, when taking the family out for a daysail, I noticed that the temp. was running at 170+ deg. Not a big difference, but worth checking out. I pulled the cover off of the pump, and the impeller was missing 2 blades. (found one, other is in heat exchanger limbo I think) Replaced it and the temp went back down to 162 on the trip home. You can also check the strainer..easy to do and very accessible. You also might have grass or an obstruction (baggie) in the thru-hull. Just some thoughts.
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