adding fresh water cooler to genset.

The genset on my boat is seawater cooled. thinking i would like to revise this to a fresh water cooled system. not a fan of seawater through an engine. This is a yanmar genset. It has 1100 hours on it already so damage may be too late. But maybe can get many more years if protected now. Has anyone added their own cooling system to a seawater cooled genset?
this would require then a new pump for the seawater, exchanger of some sort, a freshwater holding tank,
what kind of pump to use for the sea water.?

Thanks Ed

Can you post a link to the generator or just post some pictures of the generator.

Ted

ASK the Mfg , there probably is a kit.

Mach_cat said:

The genset on my boat is seawater cooled. thinking i would like to revise this to a fresh water cooled system. not a fan of seawater through an engine. This is a yanmar genset. It has 1100 hours on it already so damage may be too late. But maybe can get many more years if protected now.

Click to expand...

Might get many more years out of it if you do nothing. 1100 hours on a genset in a 1981 boat (assuming original) isn't very many hours... could last another 30-40 years -- without changing anything -- at that usage rate.

And another option, depending on access, is to just use it 'til it dies... then replace with a new freshwater-cooled genset at that point.

Just an alternative viewpoint for consideration...

-Chris

Mach_cat said:

The genset on my boat is seawater cooled...
this would require then a new pump for the seawater, exchanger of some sort, a freshwater holding tank,
what kind of pump to use for the sea water.?
Thanks Ed

Click to expand...

Ed
What make / model? Was it available w/ FW cooling as an option?
Maybe exact parts are avail - possibly even salvage parts off a "junker"?

Back in the day of car style gas engines stuck in boats ,

7 years was considered the "normal" block life for sea water cooled.

The point at which replacement was more efficient than repair.

They installed very low temp thermostats to keep the salt from closing water passages..

If cost is an issue, there are several companies making replacement heat exchangers. You can find used ones on ebay. One made for your engine or bigger would work. Also keel coolers work. Keel coolers are usually several tubes mounted against the hull that transfer heat directly to the outside water. Heat exchangers require a 2nd pump, keel coolers usually use the existing circulation pump. A Yanmar kit would probably be the easiest and the most expensive.
Whatever you do, the engine probably needs to be flushed with a compound that dissolves marine growth and rust.

Lepke, thanks for your thoughts. A keel cooler has crossed my mind too. Our water here in the PNW is certainly cold enough for that.
Not sure how many lines I would need for the heat transfer. Wonder how much drag that would add to the boat. My old Catalina 30 had a seawater cooled engine which I later replaced. You just never know when they rust through from inside out.

Dont think running hours, think time in years in salt water.
If it still flows and cools and no leaks, then it is worth doing this conversion.

I rebuilt an old Onan 6500 watt MCCK from a late 60's boat given to my by the marina.

Now it was extremely stopped up with rust. I scraped out the block and dissolved the rust from the heads by soaking them in white vinegar for a few weeks, pressure spraying, scraping and putting back into the vinegar.

Here is a picture album and at the end video of it running on my deck at the house.
I just did this for some fun, not really sure what to use it for. I could use it when power goes out at the house, but already have two other gens for that. I would not want to put it back in salt water without using a heat exchanger or keel cooler. It needs a new rubber impeller, going to get a globe impeller made of 'Brandonite' someday, they are better with heat than the OEM and last longer.

Album
https://photos.google.com/album/AF1QipPC_KbtBMDtzsLVpHJbgX5YVicIxJtYP9v88hAk

Video of it running
https://goo.gl/photos/wEfNYWRYPPbzberz6

Minimally, start fresh water flushing now prior to longer shutdowns. If it is not overheating now, chances are good that an OEM kit will do fine. Does your genset have a cover on front of engine that hides a PTO spline? A gear driven RW pump would be nice to have.

Keel cooler sounds good here. Make one out of galvanized pipe, long 3/4 inch copper pipe would also work.
The black neoprene rubber impeller, some don't like hot coolant, they fail, crack the vane base.
Consider the blue Globe impeller as it can handle hot coolant better, neoprene max operating temperature is 212.

Rubber Material Reference, Neoprene, EPDM, Buna-N, Silicone, SBR, Butyl, Natural Rubber, Gum Rubber, Hypalon, Urethane, Viton, Fluoroelastomer, Fluoro silicone, Hydrogenated Nitrile, Carboxylated Nitrile

Somewhere I had the Globe impeller temp max but can not link it.

Sdowny, any idea how many ft of pipe would be needed for a keel cooler?
What diameter? I would think smaller diameter for more surface but how much length.
What does a keel cooler do to overal speed. My cruising speed is 7.

Mach_cat said:

Sdowny, any idea how many ft of pipe would be needed for a keel cooler?
What diameter? I would think smaller diameter for more surface but how much length.
What does a keel cooler do to overal speed. My cruising speed is 7.

Click to expand...

Yes, read this thread.
Keel cooling

Examples of people who have done this and calculations per 5 hp. Seems the pipe does not need to be real long.

Thank you! That was the info I was look for!

Our 6-71 has keel cooling with (2) 20 ft lengths of 1 1/2 water pipe under the hull.

The std engine coolant pump is fine no extra pump is required .

Some use a sea water pump to feed a wet exhaust which would be quieter for a noisemaker than a dry stack.

Why fix what isn't broken? I think the key to long life is regular use. We had a saltwater cooled gas engine in a runabout that lasted 17 years, and it only died because the boat sank. (We no longer owned the boat).

I had a Yanmar salt water cooled engine in the sailboat that I built in 1977. In 2007, after 30 yrs, the owner worked at a Yanmar dealer, so with easy pricing, he repowered. His teardown of the original engine revealed no problems after 30 yrs, and he said it likely would have gone another 30 before the salt buildup or corrosion would have ended its useful life.