Yanmar GM Series 1GM10E

[Robert Miller]

I am thinking about repowering my Stonehorse with the 9HP Yanmar engine. (Yanmar GM Series 1GM10E)

Seems like a good fit... light, small, etc.
Truth be known, there are few other choices for a 23' Stonehorse Jr.

I am concerned, however, about only raw-water cooling.
Does anyone have any experience with this engine?
Anyone else share my concern about raw salt-water cooling for longevity?

Thank you.
Robert Miller

That is a great engine. I had one in my 30-foot ketch and one in my 26-foot O’Day. If you want you can rig up a heat exchanger and make it a fresh water cooled engine, but I never had any problem with it as raw water cooled. The only thing that ever went wrong with the engine was the fuel line that runs under the engine rusted out and had to be replaced. This happened on both of the engines.

[Robert Miller]

"but I never had any problem with it as raw water cooled."

To distill the question to its simplest...
Does raw water circulating around the block suggest decreased longevity?

A coolant mixture would contain anti-corrosive ingredients specifically aimed at increasing engine life. Without this, would engine life not be decreased?

I guess that is the essence of my discomfort ... and is the thing keeping me from moving forward with this engine.

Although, as you say, a heat exchanger could be installed next to the engine... (there is one mounted there for my present engine), it will need a pump for the raw water that is separate from and in addition to the pump presently on the engine which will then circulate the coolant around the block.

The engine doesn't provide any additional place to belt an additional pump... how to do this? Is it practicle? Is it necessary?


Thanks.

Robert

In the beginning there were only raw water-cooled engines. Some of those are still around and running. Yes the engine will not last as long as a fresh water-cooled engine and it will not run as well. As it ages the scale that builds up from rust and crud will cause it to run hot. In a practical sense how long do you expect it to last? The chances are it will outlast the boat. To make it fresh water-cooled means that you have to add an expansion tank and second water pump for the raw water side. You can take the guard off the alternator and replace the alternator-mounting bolt with a longer one to hold a bracket for a jabsco pump. Or you can run an electric pump for the raw water side. If it were mine I would just enjoy the sailing and ignore it.

Robert,

I have been sailing with a seawater cooled 1GM10 in 3 seasons without any problems at all.
I can only recommended this little workhorse - a little noisy maybe.

If you, however, want do do something about the seawater cooling - you can by a heat-exchanger kit from swedish Martec
http://www.martec.se/ click on "kylningar"

Regards
Henrik.A