How often do you flush your raw water side with Salt-Away or equivalent?

[Kokanee]

I recently discovered that my Jabsco water pump">raw water pump shaft corroded badly, and required replacing with only 520 hours on the engine. I later found out that the shaft is manufactured from grade 431 stainless steel. This stainless is hardened but is not recommended for extended use in salt water ???. Since then I have started flushing with fresh water if the engine will not be used within the next few days or more. My engine (Vetus) does not contain any anodes.

A couple times a year, I add a de-salting agent to the bucket of fresh water I flush with just to minimise any salt buildup.

[rjlagden]

My last boat had a Volvo 2003 29 hp motor which I checked over when I bought the boat. I found the engine anode was pretty much all gone and the gallery it sat in was blocked with salt. I rigged up a system to flush the motor with fresh water and then left a Saltaway solution in it for a week or so. Next time I ran the motor I could see salt being flushed out through the exhaust. I did that three or four times over the next month or so and by then the galleries were totally clean and I could put in a new anode. After that, if I was leaving the boat for a few weeks I flushed it through with the Saltaway solution and had no problems over my next 12yrs of ownership. So flushing works!

[slowpoker]

Even an outboard motor used in salt water that is flushed with a fresh water hose after every use, when taking apart the foot to replace the cooling water impeller once a year or so, you will see some salt deposits, aluminum corrosion and even marine growth although it never gets to any temperature to precipitate anything harmful. So, although not many of us flush the raw water side of our coolant cooled diesel engines, maybe we should, every year or so, run it with some diluted acid water and let sit for an hour or so to dissolve crud and then replace hoses again and run normally in sea water to test hose clamp connections and flush the acid solution for our next outing. Maybe some day we will get to do that, huh?.

[CarlF]

15 years with 3 different boats with Yanmars and have never flushed. Engines have all run great and never had overheating problems.

With 6 years and 2200 hours on the current Yanmar 4JH4, I'm thinking of giving it its first flush using Barnacle Buster because I'm running out of projects during Covid.

I'll be interested if I see any difference - although I'm not sure exactly what that would be since it never overheats.

[gonesail]

why would you flush it? it's not an outboard motor

[wingless]

The obscenely expensive raw water cooled exhausts on my boat had a three to five year life, before requiring replacement.

It was designed to retain salt water 24/7/365 w/ no way to drain and no way to flush.

At the last replacement cycle I had enough and I redesigned the exhaust, to now being possible to drain and possible to flush.

After every usage I drain the raw water, flush w/ fresh water, followed by soapy water, then Salt Away. I then drain the water, ready for the next usage.

At the last disassembly for internal raw water passage inspection after four years of usage I discovered the parts still look brand new. At this point I would be trying to justify getting additional usage before discarding and replacing.

My redesign and maintenance appears to have made these parts now last the life of the engines.

[wingless]

Originally Posted by wingless

At the last replacement cycle I had enough and I redesigned the exhaust, to now being possible to drain and possible to flush.

My redesigned exhaust is stored and operated only with unmodified OEM Mercruiser UL-listed components.

There are not any kludge plumbing solutions that will silently fail, permitting water ingress and risking the boat sinking.

[Suijin]

Thanks for all the replies.

I asked the question because I too have never flushed the raw water side, and wanted to know if others did. I change my zinc in the heat exchanger religiously, as well as disassembling the exchanger periodically for inspection.

I think simply put that flushing can't hurt, and if it encourages greater longevity, then it's worth it. I replaced all the marinized parts on my Universal M50 a couple of years ago and while not terribly expensive, some parts were difficult to get. I did a Salt Away flush at the beginning of the process and a large amount of crap came out. The last time the engine was flushed was 7 years prior.

As for the person asking if I'd ever seen anyone flush their engine in The Bahamas, I'm not quite sure what your point is. I've not noticed any elevated knowledge level among the people who own boats here such that I would trust their opinion on best practices. In fact, probably the contrary.

[hpeer]

FWI.
Yanmar 4JH4. The engine had 672 hours when purchased. At 2,000 hours I had a Yanmar dealer do a Preventative Service on the engine. As part they took the cooler off. There was an entire impeller in there, the vanes anyway. Apparently the PO had tore up an impeller and just didn’t worry about the missing bits. I had never experienced a damaged impeller. The engine had cooled fine and I didn’t notice much of any improvement after the junk was removed.

The service guy ran some degunker through and cleaned up the cooler.

I’m a little more careful about my impellers now.

AND

The small boat has a Volvo MD-7A salt water cooled engine. Last year it was over heating. I removed the exhaust manifold and descaled it using Ospho, I reassembled it and the flushed the engine. Pretty much the same kind of thing as you see in the promo video above. Lots of out gassing. The engine now seems to be passing much more water and I can see the thermostat working as intended.

Now that’s a 35 yo engine and I don’t know if it was ever properly descaled before.