BoatUS Flushing article

I read a number of posts from the Suzuki forums and no-one recommended running the engine when on the flush ports. Another issue is getting the engine hot enough to open the thermostats...
Click to expand...

IIRC, I was told by Matt @ Kitsap not to run the engine if I hooked up only to the flush port (2006 Suzuki 150). This was when we purchased the boat. He told me the flush only goes through the engine/exhaust and not the impeller. Now if my memory is wrong, I'm sure someone will let me know.

When we first got the boat, I only flushed via the (easy/lazy) flush port. Then I began using "Salt-Away". Their instructions are to use muffs, run a fresh water flush until the thermostat(s) open @ idle, then flush w/ the "Salt-Away" for 30 seconds after you see it's foaming exiting the prop exhaust. They also say to not rinse/flush the product away, but to leave it in the engine. I do this each and every use. A little more work and a few cents, but I feel it's worth the effort. I also use it to rinse the boat and trailer, using a yard misting nozzle. I no longer see dried salt on the boat the next day; I used to see it seeping out from the rub rail, even after a good washing w/ soap...so it has to be working. :wink:
 
Just a general question about flushing: Is it really necessary to flush the impeller after use in seawater? That water never gets heated, so even if it dries out, the salts are the same as when they arrived. Just tilting the O/B into the water ought to deal with that.
If I figure out the reactions in heated seawater correctly, I think the bicarbonate (soluble) would decompose to carbonate, which then precipitates calcium and/or magnesium as their carbonates (insoluble.). Those comprise the scale one used get in tea kettles, back in the days when one had kettles and drank tea. I suppose the buildup in engines is slower, because the water is cooler than boiling hot, but they run longer than a tea kettle. :wink:
I think that is what Saltaway attacks, and why it foams - destroying carbonate deposits and forming carbon dioxide. CRL does that, but it seems too strong an acid for use on our treasured aluminum motors. :shock:
 
I do like to get the salt out of the impeller housing--agree with what you say about the salts--I have never done an analysis on the composition of what is left. But sea water is 85% sodium chloride--only 7.7% Sulfate, 1.1% potassium, 1.2% calcium and 0.4% bicarbonate. Having looked at several motors which had large deposits, I had the impression that interaction of the aluminum was involved with the deposition. Again--I don't have the exact composition of the "salt" deposits.

The issue is that flushing with the hose does not allow the thermostat to open--running on the muffs may. I prefer not to leave the salts in the SS housing of the thermostat.

Salt a way is touted to "remove salt"--Ph is 6.2. There is also Neutra Salt--Volvo product which is similar.
 
I wouldn't be surprised if there was an aluminum-carbonate reaction. Soluble carbonates (e.g., sodium carbonate) are strong alkalis and can produce pH values equivalent to lye, which can dissolve aluminum. Some corrosion on aluminum looks bigger than the aluminum parts it replaced, but not as strong. I guess this could be aluminum carbonate in our situations.
I wonder what Saltaway and similar do to zincs? :?:
 
Always a bad idea to leave aluminum in contact with any kind of water except clean tap water (or distilled water). Trace amounts of metals, especially heavy metals including copper salts can set up galvanic corrosion which will break down the protective veneer of oxide on the aluminum. The oxide can be made thicker by anodizing, which helps protect the aluminum.

The various "marine" alloys of aluminum are much more corrosion resistant, but can still be attacked, over time.
 
Back
Top