Originally Posted by Sailingking22
I should have read this forum before sailing but luckily none of that happened to me. I hear everyone and I mean everyone who sails saying change your impeller. I changed mine and the new one sucked.....so I took it apart again and but the old one back in. Works like a charm. Plus, they work fine even with tabs broken so I don't see the huge emphasis here. When the engine overheats....change it. I don't have a temp sensor on my YSM 12 but it shuts off automatically when it gets too hot. This is usually, when I leave the seacock closed or the mixing elbow on the exhaust gets clogged/blocked which seems to happen about every 24 hrs of run time. I hear everyone praising the Yanmar engines but I've never had more trouble with an engine. The one thing I would praise is I've been able to fix everything....pretty easy to work on. Well almost....currently I'm mounting a little 8 hp evinrude to the transom...not sure whats wrong with the Yanmar now. Won't spin. Probably water in the chamber which .... rebuild or replace with something better. It's on a Hunter 30 and only ran 4.5 knots. I'd love to get something that'll get me 6.0 knots.
Sounds like you need a temp gauge or over heat alarm- give you some warning before the engine dies. Or install a flow alarm- check
and maybe install new mix elbow.