How to: Removing salt and scale from cooling system passages with vinegar

The test was to see the effectiveness of using vinegar to remove salt and scale deposits from a marine engine.
The test subject is a salt water used 1994 Yamaha 130 V4 with unknown history of maintenance until about 18 months ago. At that time I purchased the engine and have used it about 80% in salt and flushed thoroughly after every use. I recently ran the boat for about 50 miles in fresh water and then a nice salt water run about a week ago.

I filled a large heavy duty garbage can about 2/3 full with water and added 4 gallons of vinegar. The boat has a nosecone and uses a transom mounted water pickup so I disconnected the house, primed the pump, and dropped it into the water then lowered the lower unit as far as possible.

Yes, that is a little grass stuck in the t-stats. Last time out I ran through a lot of floating grass in Charlotte Harbor that gets pickup up by my transom mount pickup.

These are pics of the test subject, thermostats, and housings prior to the test.

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I ran the motor for about 20 minutes and then the temp started to creep up due the water in the garbage can getting hot. I checked one thermostat and found most of the salt gone

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These are before and after pics of the same t-stat after 20 minutes

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I continued to run the boat on and off all day for maybe an 1-1/2 hour total but didnt see whole lot of improvment. When I finished I pulled it apart again and this is the result. The scale on the thermostats simply wiped off leaving the shiny surface in the second pic of it.

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When I started, the scale (not salt) buildup was hard as iron. I noticed when I was done it was very soft...kind of gooey. There was no way I could have removed it prior to this test but after, most of it easily came out with a spray from a garden hose and I scooped some out with a screwdrive. I think going for a good run in the boat right after this treatment would remove a lot of that loosened material that just didnt get washed away idleing in a bucket.
This is the t-stat housing before the test and after a good squirt with a hose and a little cleaning.

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Heres some video I took before and after. I saw a small improvement in water pressure but I wouldnt put a lot of weight on that which could be caused by a small change in how it was idling or the water source.


http://www.youtube.com/watch?v=txPss8dJa30

Overall, I am completely convinced vinegar does a great job of removing salt and even loosens the scale buildup inside the cooling system of a fresh water cooled engine. This will now be a regular part of my maintenance program. As far as it comparing to salt removing products sold to boaters, I cant imagine they would work any better. The salt is almost completely gone which is the goal IMO.

A few words of caution:
1. Remove your prop to avoid a potential accident.
2. The water GETS HOT.
3. Dont leave your boat idleing unattended.


Here is the garbage can. The water started clear. When it all settles, I will pour off the top and post pics of what came out.

New pics added. There is a lot of "gunk" the the bottom of the can which was cleaned before the test. The white stuff came out of the opti and is pretty fine like powder. The grey and grit came out of the Yamaha. The pics dont do the amount of crud removed from the engine justice and I am sure the salt was all suspended in the water I siphoned off.

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Thats it..in a nutshell.

Very interesting test.
Thanks for the info:thumbsup:

Do you ever flush that thing ?? I mean right after use , not days later . My 2.0 liter 150 had over 1000 hours on it in salt and looked nothing like that !!!

Quote:

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Originally Posted by Tom Foley

Do you ever flush that thing ?? I mean right after use , not days later . My 2.0 liter 150 had over 1000 hours on it in salt and looked nothing like that !!!

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Think Mercury coats the cooling passages with something that helps with corrosion, when winterizing Mercs the drainplugs drain fine( sterndrives ). OMC's and Volvo's have to be probed and passages are full of rust and scale, not the case with Merc.



Dave

Tom, I am OCD about cleaning, flushing, and maintaining my boat. Remember though, this is a 17 year old motor that I dont know the history on but likely a salt water motor all its life. Yamaha are known for corrosion issues. I either flush right at the ramp (they have a hose there) or a few minutes later when I get home.

Great information.:iagree: I had wondered about using some of the commercial drain cleaners to get a similar result. My only concern would be any possible damage to the water pump impellor.

Quote:

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Originally Posted by Smoking Joe

Great information.:iagree: I had wondered about using some of the commercial drain cleaners to get a similar result. My only concern would be any possible damage to the water pump impellor.

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I wouldnt use anything like that. You could do some serious damage with a strong acid. I beleive my vinegar/water solution was about 10% and worked very well.

Another tip that has worked very well for me is to use vinegar when washing the boat at the end of the day. I use a "dial-a-sprayer" hose end type attachment used for gardening. I fill it 1/3 with inexpensive Blue Coral car soap and 1/3 with vinegar. Set the dial to where you just start to get some suds when spraying down the boat. It works VERY well for removing salt from the boat. There is a huge difference in the amount of salt on my black motor cowlings if I do this vs. just spraying them down with water alone. I spray the whole boat, t-top to bottom and then brush what needs it. I also have hot water plumbing outside which also helps remove salt.

The only problem I have run into with using vinegar is the smell. Reminds of an old commercial:

http://www.youtube.com/watch?v=N91XsdrBqUY

New pics added after I siphoned the water off in the garbage can.