Salt Away?

[Doc Stressor]

I remember my battles with Pyramid Lake deposits very well! If you guys think that saltwater is a problem, you have seen nothing like what an alkaline lake with 25% the conductivity of seawater can do to an engine.

The problem was that I couldn't flush the engines until I got home. After a ~1 hr drive, the carbonates had already dried onto the water jacket surfaces, the thermostats, and anything else that had come in contact with the lake. Flushing through the port with a hose never let water get to the top of the thermostats, so they would cake up and stick in the open position every year or two. In the first couple of years, I would fish Tahoe a lot during the summer when Pyramid fishing was closed. The super-low conductivity Tahoe water would clean out the deposits over the summer and I had no problems. But after I got bored with Tahoe and started fishing other lakes and the ocean over the summer, the deposits became more of a problem. Once the big engine started overheating, it really got bad because high temperatures increase the rate of the salt reactions.

I ended up needing to do a long tub flush with a commercial descaler. Things got a little better when I switched to flushing with the earmuffs, which let the thermostat open. But Pyramid is a constant challenge. I worked on several of my friend's engines and some needed to be partially disassembled and soaked in a strong acid to get them to run cool.

Flushing by running the engine in a tub of vinegar or other acidic solution every once in a while is good preventive maintenance. The high temperature accelerates the descaling process. Add a little detergent to act as a surfactant. It speeds up the process.

 

[PNW_Drifter]

Have you looked at the MSDS sheet for Saltaway. It's expensive soap. My father's a chemical engineer so I asked him what cheap chemical I could use to remove deposits. I can't afford $20/half gallon of soap. He basically agreed with many here. I used vinnegar 4 gallons or more in barrel with the thermos open for a nice steamy bath. Then my homemade salt away is dish soap in the Saltaway cup mounted on hose.

People who defend saltaway have bigger budgets than me. I don't believe for a second that it has any real corrosion inhibitor as it's not listed on their MSDS. Also it would all be washed away.

KY, I had a really salty 2007 F150 from a Marina boat 4 years ago. My zincs looked worse than yours, thermostats, better but stuck. My theory is it was only flushed on the port vs muffs. That's what you can do in a marina and is easier even on a trailer vs the muffs. Thermostats suffer in that condition.

 

[Harpoon]

Water treatment for "harness" is a very big business. That isn't salt, I bet if you taste it you'll agree. You may want to flush with CRM or some chemicals used for boiler feed water. Even a mild vinegar solution may be effective.
The worrisome part is that eventually hardness build up will limit your ability to cool the engine.

 

[Ky Grady]

Probably going with the 6-8 gallons of vinegar and a little Dawn in my 100 gallon water trough that I have left from horse riding days. I'll do it in the spring during my first start up before the season.

 

[Doc Stressor]

OK, I just looked up the most recent MSDS for SaltAway. They have changed the formula a couple of times over the years. I was surprised to see that it no longer contains trisodium phosphate and a few other early components.

Here is the relevant information:

3 Composition/information on ingredients

Non-Hazardous Surface Active Agents 5-10%

65997-01-5 Corrosion Inhibitor 5-10%

Non-Hazardous Coupling Agents 5-10%

7732-18-5 water, distilled, conductivity or of similar purity 70-90%

pH-value @ 20 °C (68 °F): 6.2

It is only slightly acidic. So it would not be effective in rapidly dissolving a significant scale build up.

The surface active agent would be a non-hazardous detergent that would help wash away any particulate matter, any oil or grease, and allow the mixture to wet the surface of the metal effectively.

I was able to identify the corrosion inhibitor by looking up the CAS number. It turns out to be Tall Oil, which is a type of fatty acid based soap. It is mostly oleic acid. Fatty acids can protect metal from corrosion during storage if they are allowed to dry down on the surface. And this is exactly what the SaltAway instructions tell you to do. Don't flush with water after using SaltAway.

Coupling agents in this application are typically chemicals that chelate (bind) divalent ions such as calcium and magnesium and hold them in solution. The common household descaler CLR uses this approach. These type of chemicals can remove scale, but it typically takes long soaks at high temperatures to be effective.

So the recommendation to use SaltAway from the git-go and every time to prevent salt build up seems to be spot on.

 

[Ky Grady]

So Doc,,, in my case of late in the game with 1260 hours on a 2004 motor, I'd be better off with the vinegar/dish soap flush and go on with life? When I repower, I can start out with Salt Away for my occasional saltwater adventures, and keep that regiment going forward?

 

[Doc Stressor]

That's what I would do.

 

[seasick]

TSP has been banned in many states, NY for example but surprisingly it's still OK in NJ.

 

[HTHM]

What about CLR?
https://clrbrands.com/en-US/Products/CLR-Household/CLR-Calcium-Lime-Rust-Remover

 

[max366]

Probably OK but it's a weak acid w surfactant and chelating agents, as Doc mentioned above. You'd need a lot of it to be effective. it's meant to be put in a pipe full strength and let it sit to remove scale or directly (100%) onto a surface to clean it.
BTW, turns out vinegar is only about 8% acetic acid so keep that in mind when using it- especially if it will get diluted even further by the water for cooling.
I've been looking at using citric acid, readily available on Amazon, and it turns out in the right concentrations, it will remove scale and leave a corrosion inhibiting layer on the aluminum. I need to do more to finalize the amounts but it looks interesting as a Salt Away alternative when mixed with some surfactant.

 

[Doc Stressor]

I would not use citric acid with an anodized aluminum surface. It is sometimes used as a corrosion inhibitor for aluminum, but it must be at neutral or slightly alkaline pH or it will remove the passive aluminum oxide layer and many types of anodizing alloys. It chelates aluminum ion. It's great for cleaning and re-passivating stainless steel, however. I use it a lot for cleaning up boat hardware although it requires a long soak.

CLR takes too long to be an effective engine descaler. We used to use it to remove calcium deposits for glassware back when I had a laboratory. We would use it full strength is a heated water bath and it would take overnight at 60 degrees C to do the job.

Acetic acid (vinegar) will not harm aluminum and shouldn't affect anodization alloys used for corrosion protection.

Sulfamic acid is typically what is used in commercial descalers. It works pretty fast. But I remember helping a boat dealer in California who had taken an overheating Pyramid Lake engine in trade. We ran the engine for 4 hours in a tank with descaler to solve the problem. It only took 1 hr to clear my 90 Honda.

 

[max366]

I agree that citric acid used incorrectly can damage the aluminum surfaces so the question I'm looking at - is there a concentration to use and for how long to prevent damage yet remove the deposits. This is what I'm checking into. I found an interesting research paper that indicates it can actually reduce the Al corrosion rates - here's what it says:
"The experimental results showed that citric acid inhibits the corrosion of aluminium in NaCl solution and the inhibition efficiency depends on its concentration."
Citric will certainly dissolve Ca/Mg scale so if will also inhibit corrosion of the aluminum from the salt water, perhaps it's a good solution (no pun intended!). I'll work out the details and post the info if it looks feasible.

 

[Doc Stressor]

Citric acid at neutral pH (usually neutralized with sodium hydroxide) chelates Mg++ and Ca++ ions and prevents them from forming scale in industrial applications. Since you have an open cooling system in an outboard, there is no way to use it to protect the aluminum parts. It is not as effective as some other chelating agents in removing scale once it forms.

Citric acid itself is in the protonated form rather than a salt. The resulting low pH can corrode aluminum. It can be used to remove the dark patina aluminum oxide layer that forms on bare aluminum hulls. But it needs to be rinsed off as soon as the stain is gone. The dark aluminum oxide layer starts to e-form in the presence of oxygen and moisture. It looks bad on hulls but is actually protecting the aluminum alloy from corrosion.

Citric, oxalic, and sulfamic acid can be used to remove scale. They are stronger acids than acetic acid (vinegar). But the effect on the protective anodized layer put on the water jacket cannot be predicted. That is also the case when using even stronger acids like muriatic (HCl) and phosphoric acid. They will dissolve the scale, but if you wait too long before flushing with fresh water or a baking soda solution, they with remove the anodization and corrode the underlying aluminum.

 

[PNW_Drifter]

Great conversation. I'd be all ears for an inexpensive and effective descaler that I can use once in a while.

 

[Ozz043]

Interesting thread.
I used Salt-Away after each use in a fresh water highly alkaline lake for a year. Then my check valve for the wash down system on my Honda BF200 got stuck from the alkaline deposits.
My mechanic told me to use vinegar instead.
When I ran the motor in a 100 gallon tub with 6 gallons of vinegar, I couldn't believe how much crud came out in the water.
After using only vinegar for a year then running in tub next season, there wasn't even a spec of a deposit, so at least I know that works for my situation.

I too have heard that a ratio of Vinegar works .... something To do with the ph

 

[trapper]

I use Salt Away after every salt water run. Spray the disk brakes and trailer springs after launch and flush outboards on getting home. Never understood the issue with cost? I have thousands of $ invested in my boat motor and trailer and $60 a year does not seem to equate as too expensive as it appears to do the job for me. Clean thermostats etc. Only like vinegar on my chips!!

 

[Fishtales]

The vinegar and soap sounds like the best solution cost and salt effective. Like everything, don't over do it.

 

[leeccoll]

I decided last season to use vinegar on my motors every other time I used them, and the pee stream seemed weak the other day. After putting an "excavator" up there and seeing if it improves, some deposits came out on it.

Today I gave my engine the "spa treatment".

10 gallons of vinegar and a bit of detergent.

I noticed some deposits in the 100 gallon trough at first. After 20 minutes these deposits totally disintegrated.

Ran the engine mostly at idle, and upped it to max 2000 RPM at intervals for 40 minutes total.

Clean as a whistle now, and shame on me I will be treating both engines every time they are used from here on out.


.

 

[Ky Grady]

I'm actually looking forward to doing this for mine this spring. Definitely can't hurt as I've not done a cleaning flush like this.

 

[magicalbill]

I never realized Doc Stressor is a Mad Scientist AND a boater....