Generator Cooling

[craig42]

Hello.

I am going to fit a genny and am looking for input concerning direct sea water cooled or heat exchanger cooled. I can get a good deal on a direct sea water cooled machine but do not want to buy if it's not the right thing in the long run. The engine is a yanmar.

Any feedback would be great.

Thanks

Craig

[DotDun]

IMO, salt water is acid. Heat exchangers are cheaper than engine blocks.

[Dockhead]

Our outboards are all raw water cooled, and they are mostly bulletproof. I wouldn't jump to the conclusion that this is automatically a bad thing. The only thing is, I have never even heard of a raw water cooled genset. Mine (a 6.5kW Kohler) is fresh water cooled, like every other installed genset I've ever seen on a sailboat. What in the world kind of genset is that?

[DotDun]

Originally Posted by Dockhead

Our outboards are all raw water cooled, and they are mostly bulletproof. I wouldn't jump to the conclusion that this is automatically a bad thing.

Most outboards are not cast iron blocks. Most diesel generators are. Besides, the owners manual on your outboard suggests to flush it with fresh water after use.

[jannpage]

It is not a very big deal to change a "sea water " cooled to "fresh water" You need a heat exchanger and a water pump and a few hoses and clamps and other bits. Since often if it near impossible to find a way to drive a second water pump off the engine, the second water pump is typically an eleectric one. I find that bait pumps work well. I typically use the bait pump to pump the cool sea water. I then use the original sea water pump to circulate the hot "fresh water conecting it so the suction of the that is connected to the output of the heat exchanger and its output is connected to the original input to the engine. A relay and fuse in the electric supply line generally is needed. Lots of luck.

Cheers
Lloyd

[ggray]

I've read that raw water auxillary engines of old didn't have major issues until people installed high temp thermostats for the benefit of water heaters. So it is important that they be kept cool.

Not that I've had first hand experience!

[David M]

You asked for the long term effect. You dont want to run salt water through an engine block. For one thing there are dissimilar metals in an engine block. That reason alone is good enough.

[atoll]

better to use an air cooled engine and put a salt water intercooled radiator

[craig42]

Thanks, then I will be sure to fit a fresh water cooled machine.

Craig