yanmar SB 8 overheating

[ciriaco]

Last week I took my boat out for the first time this year and the engine overheated and conked out as I was about ready to put up the sails. The boat had been in the water all winter and part of the time locked in ice. I checked to see if water was pumping through and coming out the exhaust. It was shooting out as usual and yet the engine was overheated and stopped. I put up the sails and had a short sail in light winds; enough to get me into the channel. I turned on the starter and it started back up. I remembered I had gone out on full throttle and this time I came in with engine at a low rpm. I am wondering if anyone has had this problem or has an idea what may have caused it. I am not sure if I should risk going out again.

 

[Bill O'Donovan]

Mixing elbow

The mixing elbow may be caked over nearly solid, choking off water even though some is coming out the exhaust. If the elbow hasn't been replaced in five years, that could be the problem. Like a heart attack, it sneaks up on you unexpected and cuts off the blood supply. Fortunately, you can toss the old one and buy a new mixing elbow for $150. Try that with a heart.

 

[Gene B]

Engine Overheating

Check the archives. This topic has been well documented/. Bill is probably right. Check out Steve Dion's excellent pictures and descriptions in the archives. I removed my mixing elbow, sand blasted it, and overheating problems vanished. Don't forget to replace the gaskets, though.  Also, even though you are getting water out the exhaust, it may not be all that is required. Check your impeller and also your raw water intake. I once had a clog of seaweed before the strainer. Looked like a cheap cigar when I dug it out. Water still go through, but not enough. Check the simple stuff first.

 

[ciriaco]

engine overheating

/thank you Gene and Bill for your suggestions. I will be out to the boat and check these simple things first. Happy sailing this season.ciriaco