Yamaha over heating problem

[DENNISP3]

I have a 1987 Yamaha 150 outboard that is over heating when you run above 4800 RPM. I change the water pump and I now believe the problem is a build up of salt deposits in the heads! In lue of removing the heads and buying new gaskets etc which will cost $170.00, I have another idea to possibly correct the problem. If I remove the thermastats and pour some salt eating solution in the heads to eat out the salt this may correct the over heating by increasing water flow. My question is has anyone tried this and what type of solution will be effective. <br /><br />thank you

 

[moderator1]

Re: Yamaha over heating problem

Moving to Yamaha questions.

 

[jim dozier]

Re: Yamaha over heating problem

I had a similar problem with my Suzuki. I removed my heads and after manually scraping the aluminum and salt deposits out of the head it is my belief that if they are clogged to a degree that it is affecting flow, manual cleaning is necessary. This stuff is tough. It is mainly aluminum carbonates and aluminum hydroxides which are byproducts of the corrosion of aluminum. There may be some salt mixed in, but salt is not your problem because salt is soluble in water. The aluminum compounds are not. The use of something stronger like acid is not a good idea because the aluminum metal is also soluble in acid. The acid will eat away at the joints and cracks which have more surface area and do damage where you don't want it and probably not do much to the clogs. I put some acid in a test area of the cooling channels of my head when it was off and the deposits do not dissolve easily.<br /><br />There are products on the market like Salt Away and I have no experience with them, but I know the chemistry and it is my guess that if they have some utility it is in the area of prevention and not cure.