Yanmar 2QM15: How can I keep it running forever?
My new-to-me 1981 Spirit 28 has a 2QM15 (raw water cooled). Not sure how many hours are on it, since the boat didn't come with an hour meter (PO installed one, about 80 hours currently). Based on boat history (lots of hard storage and marina time), my guess is that the engine has less than 1,500 hours. Visually, it looks virtually new (no rust or visible corrosion anywhere), and it runs very well (although it's a bit hard starting when cold, which seems to be normal for these non-glow plug motors).
Given the high cost of repowering, and its apparent good condition, I'd like to keep this motor running for as long as possible. Based on my internet research, the most common failure modes seem to be corrosion based (exhaust manifold (part not readily available) and mixing elbow), along with head gasket leaks (perhaps also related to corrosion).
A fresh water cooling conversion would appear to reduce the rate of corrosion, but it doesn't appear that conversion kits are offered any longer, so I'd need to engineer my own (not sure the payback would be worth the cost and hassle).
Other than standard routine maintenance, a periodic chemical flush (Rydlyme) appears to be recommended by many. One person suggested an electric pre-oiler (though excessive wear doesn't seem to be a primary failure mode on these engines).
Any other recommendations?
Last edited by Rusty123; 04-07-2013 at 04:44 PM.