? Chemical to clean water passages

[Tgsx750f2000]

I was wondering if there is some kind of chemical you can use to clean the passages in my 90hp Yamaha 2 stroke? I am trying to avoid removing the head cover, afraid I will break some bolts. I can see through the opening of my thermostat hole a rust colored build up that I can scrape with my fingernail and it comes off. I am fighting a overheat alarm problem at 4500 rpm and higher. Changed water pump, heat sensor, thermostat, And checked poppet valve.

[robert graham]

Saltaway is a chemical product for removing internal motor mineral/corrosion deposits, but with any acid-based cleaner, the trick is to reduce deposits without harming the metal parts. Make dead sure your water pump, thermostat and pressure control valve are functioning correctly before resorting to chemical cleaners. Good Luck!

[yamatech44]

Actually, the best is Volvo's(have to go to Volvo marine dealer) is called
Neutra Salt and seems to be harmless, even to aluminum....have used it many,
many times for salt removal, from a/c units to outboards....just pull the t'stats and pour in....you can dilute greatly for preventive flushing or use straight to dissolve salt/mineral buildup....works wonders, you can leave in for awhile(10 minutes or 2 hours, won't hurt) and then rinse with hose in t'stat hole to rinse one way, then put motor on muffs and start with t'stats out and blow out that way....you'll see the chunky stuff come out. Have used both and would say
Neutra Salt is about twice as good.

[99yam40]

This thread was interesting, you might want to have a look at what he used and how he did it

http://www.yamahaoutboardparts.com/f...g-th19434.html

[Tgsx750f2000]

I will be flushing my engine sat. With vinegar and water. I will post the results when I test it.

[robert graham]

I doubt vinegar is strong enough to remove much calcium/mineral/corrosion deposits, but give it a shot....you could strengthen your acid with a dose of Muriatic Acid...when you're done, run some backing soda solution through it to neutralize the acid. Good Luck!

[tmann45]

Saltaway is a chemical product for removing internal motor mineral/corrosion deposits, but with any acid-based cleaner, the trick is to reduce deposits without harming the metal parts.

and

I doubt vinegar is strong enough to remove much calcium/mineral/corrosion deposits

First off, I would not consider Salt-Away an acidic chemical, the pH is only 6.2, water is +/-7, completely neutral. Vinegar has a pH of 2.4, some where around 5,000 times stronger acid.

Secondly, Salt-Away is only advertised to remove salt and leave a corrosion protection film on the surface, not remove any mineral deposits or corrosion. Truth in advertising at work. :-)

[mitch]

Have look at this sounds plausible using vinegar.

How to: Cleaning your cooling system with vinegar - The Hull Truth - Boating and Fishing Forum

[Tgsx750f2000]

I tried flushing with 4 gallons of vinegar but nothing changed.

[yamatech44]

Dude, just go get the Neutra Salt....just get a quart, mix 2 to 1 water over product, and do like I said, done many times to different customer's engines, from mild to SEVERE problems....works, nuff said already.

[robert graham]

I tried flushing with 4 gallons of vinegar but nothing changed.

After 13 years of chemically cleaning boilers,A/C units and heat exchangers, a few things to consider: composition and amount of deposits, calcium, iron, aluminum oxides,salt, etc., strength and type of acid, temperature of acid, circulation rate and length of time of circulation, neutralization of acid and flushing of the system. Good Luck!

[Tgsx750f2000]

Well come to find out that wasn't my problem, it was my battery causing a short and setting off my overheat alarm. Go figure I fought this problem for 8 months!

[99yam40]

Seems the problem was you did not ask for help with an alarm coming in that you did not know what it was.
Could have had input from some about what all the possibilities were, live a learn

[rodbolt17]

and thats where correct rigging helps.
the yamaha digital tach shows visual indicates for overheat and oil.
if its not one of those it has to be low voltage on that engine.

[Toulla]

Yamatech44,
so you pour straight neutra salt into the thermostat housing, you wait for up to an hour, and then stick a fresh water hose into the the thermostat housing to flush in one direction only. Clear up to this point.
Now, when you run the motor with the ear muffs, is the thermostat housing installed at this point or not? Thank you much for your help.