SailNet Community

SailNet Community (http://www.sailnet.com/forums/)
-   Diesel (http://www.sailnet.com/forums/diesel/)
-   -   Raw Water Cooled for 35 Years? (http://www.sailnet.com/forums/diesel/97489-raw-water-cooled-35-years.html)

CarbonSink62 03-11-2013 12:11 PM

Raw Water Cooled for 35 Years?
 
I went to look at a boat last weekend (a Bristol 29.9) and loved it until we talked about the engine.

The ad said "diesel with 800 hours" and I thought that might mean a newer engine (how would I know how many hours a boat might be motored in a year?). Well it is 800 hours on the original 1978 engine and the boat has raw water cooling.

Looking online*, I see that maybe the 800 hours is not an issue because a well maintained one can get 5,000 (if you believe the internet) but the 35 years of salt water going in and (hopefully) out still scares me.

After the visit, I told my wife "Lovely boat, but we'd need to replace the engine."

Was that correct? Would a reasonable sailor replace an engine in this situation or could I just make sure it runs and trust it for a few years?

My mooring is on a river with a swift current and 2 draw bridges, so running the engine to failure is not an option.

Finally, if saltwater corrosion is going to be the cause of death, what are the initial symptoms? Is there a way to determine the level of corrosion?


* The Life Expectancy of the Marine Engine - BoatSafe.com

marcusc130 03-11-2013 12:17 PM

Raw Water Cooled for 35 Years?
 
My 1978 San Juan had the original yanmar raw water cooled diesel in it. That engine ran like a top. I never had one issue with it, besides a problem caused by some bad fuel. As long as it is maintained properly, I don't see a problem.

jrd22 03-11-2013 12:49 PM

Re: Raw Water Cooled for 35 Years?
 
My father replaced the original raw water cooled Volvo in his 1970 Contest in about 2008. Never had any problems with the cooling system, it was the transmission that went out and parts were no longer available. So the cooling system per se might not be an issue but other components could cause reliability issues. It sounds like you need to use the engine and if you are going to worry about it every time you use it you might as well replace it for peace of mind. Buying a boat with the intention of installing a brand new engine has a lot of advantages if the economics work out OK.

casey1999 03-11-2013 02:16 PM

Re: Raw Water Cooled for 35 Years?
 
My engine is a 1980 Yanmar 3gmd (raw water cooled). I also depend on it to get into and out of harbor safely. Was also concerned about engine when I purchased boat. I did go through the cooling system (repalced raw water impeller, all hoses, inspected strainer, replace thermostat, carry spare raw water pump, replaced engine zincs).

I also flush the engine with fresh water on return to dock. For this get a bucket and install a hose fitting at the base that you can run your engines sea water pump suction line to. When you return to dock cool the engine down by using fresh water. Always let engine pump the water- you do not want to hook pressure hose direct to the engine- might cause damage.

One sailor I know uses salt away to flush. He leaves it in the engine between uses. I am on the fence on this.

I have looked into my engine block and do not see corrosion. One mechanic told be these engine used good materials and things like zinc protection and they will last. The thing I like about the direct sea water cooled is they are much simpler than a fresh wate cooed. The direct sea water has one less water pump to fail and does not have a heat exchanger to deal with.

A replacement engine for a 20 hp is going to cost around $11,000 and say another $5k for install when all said and done (boat yard install with potential engine bed mods). May or may not be more reliable than what you have. The way I see it, anything can break.

BubbleheadMd 03-11-2013 02:30 PM

I think your level of caution is overkill. 40 year old, raw water cooled Atomic-4 here.

CalebD 03-11-2013 04:01 PM

Re: Raw Water Cooled for 35 Years?
 
45 y.o. raw water cooled A4 here.

kellysails 03-11-2013 05:04 PM

Re: Raw Water Cooled for 35 Years?
 
Quote:

Originally Posted by casey1999 (Post 1001181)
Always let engine pump the water- you do not want to hook pressure hose direct to the engine- might cause damage.

This is something that I was going to start to do with my engine in the near future.

Interesting, I have never heard that before, is that true? How might it hurt the engine?

casey1999 03-11-2013 05:20 PM

Re: Raw Water Cooled for 35 Years?
 
Quote:

Originally Posted by kellysails (Post 1001274)
This is something that I was going to start to do with my engine in the near future.

Interesting, I have never heard that before, is that true? How might it hurt the engine?

On an old engine, the gaskets and seals may not hold the water pressure (my dockside water hose will discharge at 100 psi). Also, your raw water pump discharges a lot less pressure and volume than a water hose, you could cause a lot more water than designed to flow into your engine. This could flood the engine cylinder through the exhaust ports (via the mixing elbow). Much better and safer to just let the raw water pump suck the water from a bucket and let it do what it normally does.

kellysails 03-11-2013 05:25 PM

Re: Raw Water Cooled for 35 Years?
 
Thanks Casey1999!

casey1999 03-11-2013 05:34 PM

Re: Raw Water Cooled for 35 Years?
 
Quote:

Originally Posted by kellysails (Post 1001283)
Thanks Casey1999!

Anytime.
I took a bucket and installed a plastic through hull fitting on it. Then, right after the engines raw water seacock I installed a "T" fitting. on that "T" fitting I have a ball vavle then hose nipple. Attach hose and run it to the cockpit where I have the bucket. To flush I attach hose to bucket and fill. then open up the ball valve and close the seacock. Because the hose fitting is at the bottom of the bucket, the hose will be full of water and no air, so when I shut the seacock, the raw water pumps pulls water from the bucket. Keep the bucket full with a hose and do not let the water level drop below the buckets "through hull fitting". This is also a good way to see how much water your raw water pump is pumping at different engine rpms. If you notice a drop, you know you got a problem with your cooling water system. Having the bucket topside makes for no problems with spills- going to rinse the boat down anyways.

Always remeber to line up your ball valves correctly- either for sea water or fresh water flush. I also put a stopper in the flush hose in case the ball valve gets opened while sailing- don't want to flood the boat.
Regards


All times are GMT -4. The time now is 12:00 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012