Do the water passages get clogged after years of use and if the
engine is under strain it will show up as overheating?
ANSWER: A MOST DEFINITE --- YES!

Your engine is probably 'salted': both in the exhaust manifold and the
internals of the engine proper. Especially if the thermostat opens at
above 190 degrees the salting process is amplified.
Sea water when heated above 150 degrees will precipitate carbonates
(salts) which CONTINUOUSLY form an insoluble coating on the engine
internals. This fouling will retard heat transfer and if the 'salt'
deposition is significant will block the flow of cooling water.

Best remedy is to drain the cooling water, then add MARSOLVE
(www.marsolve.com) circulate* this through and let sit to dissolve the
'salt' accumulations. Marsolve is commercial descaling compound that is
biodegradable and will NOT dissolve the base metal of the engine. Many
use muriatic acid to 'pickle' marine engine internals but the muriatic
will also react with or dissolve engine base metal. ALL salt water
cooled engines should be so 'pickled' every few years to remove the fouling.

Once the engine is 'pickled' make a decision:
1. Install a thermostat that opens fully at 135 degrees and suffer less
thermodynamic efficiency because the combustion chambers operate at a
less combustion-efficient state. OR
2. Plan to 'pickle' the engine every few years.

*circulate = pull the inlet water hose from the closed through-hull.
Remove the hose from the water injection port to the heat/steam rise
elbow. Put the inlet water hose, put a temporary hose from the muffler
water injection into a large bucket, pour the marsolve into the bucket
and run the engine until the marsolve fills the engine, Keep running
until the marsolve solution is warm, then shut down the engine and let
the marsolve soak. Etc.

On Mon, 11 Aug 2003 04:07:03 GMT, RichH wrote:


Once the engine is 'pickled' make a decision:
1. Install a thermostat that opens fully at 135 degrees and suffer less
thermodynamic efficiency because the combustion chambers operate at a
less combustion-efficient state. OR
2. Plan to 'pickle' the engine every few years.


I've always felt bad bringing a nice yacht to a dock then just leaving
it all corroding away for sometimes weeks at a time leaving salt in
the heat exchanger and exhaust. I don't do that to outboards and
jetboats. Why is it "ok" in nice boats?

Is there a particular reason expensive yachts don't have fresh water
flush systems on, say, a sailboat auxiliary? It's so simple to
install to simply backflush it into the sea and close the seacock,
leaving the system full of clean, salt-free, fresh water that will
absorb the salt.

These engines aren't immune.....


Larry

Extremely intelligent life must exist in the universe.
You can tell because they never tried to contact us.

Not the same ------

You flush an outboard to prevent corrosion from occurring.

You cant flush the already solid precipitated carbonates as once they
form they are insoluble in water. What you formed by the elevated
temperature (greater than 105 degrees) is ROCKS!

Thanks, I will pickle the engine, I got a copy of Good old boat yesterday
and they have an article on cleaning out raw-water cooled engines using
muriatic acid. Same technique would work with marsolve.

George Pappas
S2 9.2A "EXO"

I sued to 'pickle' all the time with muriatic (hydrochloric) acid ...
you can remove a fair amount of engine base metal if youre not careful.
Muriatic pickling does remain a valid process - just be very careful.

Mr. Catfish wrote:

Thanks, I will pickle the engine, I got a copy of Good old boat yesterday
and they have an article on cleaning out raw-water cooled engines using
muriatic acid. Same technique would work with marsolve.

George Pappas
S2 9.2A "EXO"

From: RichH
Organization: AT&T Worldnet
Newsgroups: rec.boats.cruising
Date: Mon, 11 Aug 2003 20:51:45 GMT
Subject: Engine overheat-yanmar 2qm15

I sued to 'pickle' all the time with muriatic (hydrochloric) acid ...
you can remove a fair amount of engine base metal if youre not careful.
Muriatic pickling does remain a valid process - just be very careful.

Mr. Catfish wrote:

Thanks, I will pickle the engine, I got a copy of Good old boat yesterday
and they have an article on cleaning out raw-water cooled engines using
muriatic acid. Same technique would work with marsolve.

George Pappas
S2 9.2A "EXO"


Yanmar advised not to use muriatic acid, just a mild cooling system cleaner.