muriatic acid treatment for outboard

nick1048

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Has anyone done, or had a muriatic acid flush on an outboard before? I am looking at an '88 Gulfstream that starts right up, but overheats after about 20 minutes. Just about everything imaginable has been done to alleviate the problem, but nothing has worked. Two professional mechanics along with other non-pro people have worked on it. Sounds like the last option is the acid flush to try to clear it out. Any general cost quotes? ideas, comments appreciated, thanks
 

seasick

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I assume this is an inboard or I/O. What was done? Is the motor raw water cooled?
Were risers and manifolds changed? Is there aheat exchanger?
I wouldn't use muriatic acid. There is a real risk of personal harm from, spashes, toxic fumes, acid/water violent heat generation etc.


Ther are lots of possible causes from a simple bad pump all the way up to a cracked head/block, blown gasket, blocked water chanels ( you will need to remove a head to see if the chanels are cruded up.
I would try another mechanic first.
 

no problem

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If 2 professional mechanics looked at it and couldn't repair the engine, it may not be repairable. There could be internal block or head damage. Was a compression test done? If the engine doesn't work I would price the deal as if it needed a repower. Once i owned it, if compression was good I would remove heads and clean cooling passages. Then change thermostats and water pumps. Good luck!
 

exudedude

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Have you tried whit vinegar yet... get a big barrel 30-55 gal and put about 15-20 gal of white vinegar. Run her a little at a time, let her sit, run her again. If each run time is longer you are making headway. You can save her this way. Also as last resort pull the heads and maually clean.

Both fixes are way cheaper than new power.
 

ahill

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Muriatic acid will eat thru the riser walls on severely rusted/plugged risers allowing saltwater to enter the block (I know).
If you listen to your mechanics you'll save $$ frustration and aggravation in the long run and be safe afloat.
 

Curmudgeon

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Muriatic acid will eat thru the riser walls..

Not to mention any hoses ... :?
 

gw204

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Maybe give it a few straight days of the Salt Away treatment...

Can you post what has been done already to try and alleviate this problem? I'm curious to hear what the pro's and non-pro's have tried.
 

Strikezone

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With all the boats out there for sale I would be very leary of one with engine problems. I wouldn't use muriatic acid for sure but I think the saltaway treatment may be your best bet.

If the engine has been neglected to this point what else has been neglected? Its something to think about.