Join Date: Sep 2012
Location: Bremerton, Washington
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Re: Yanmar 2QM15: strange overheating incident
I haven't pulled the thermostat yet, but have some new symptoms to post, for the sake of anyone who may read this thread in the future.
Took the boat out for the afternoon, and ran the engine for a couple hours. Like the last time, the temperature was stable, but about 10 degrees higher than normal (running about 135F, vice 125F).
I pulled the raw water strainer basket, and it looked clean at first glance, but when I looked closer, there was what appeared to be a small jellyfish in the bottom. But I think what it really was was an accumulation of bio-slime. I scrubbed out the basket thoroughly and replaced it. After starting engine again, temps seemed to drop a bit, but time was running short, and I wasn't able to perform a thorough test.
I'm still planning to pull, and perhaps replace the thermostat as part of an upcoming maintenance evolution.
1981 Spirit 28 "Bonnie Lass"