Daniel wrote in message
Ralph

Not so uncommon and may be due to a malfunctioning of the exhaust/raw
water discharge circuit.
Sometimes it is just a vent that is plugged and permits a backflow of
water into the cylinders after shutting off the engine. The water, then,
seeps between the pistons and the cylinder walls into the sump.
Sometimes this problem, if not understood early, may cause the blow up
of the engine head at the next attempt to start the engine.

I second that. Also look in an exhaust system design flaw. Could the
seawater siphon back?

Jacques
http://bateau.com

(Jacques) wrote in message . com...
Daniel wrote in message
Ralph

Not so uncommon and may be due to a malfunctioning of the exhaust/raw
water discharge circuit.
Sometimes it is just a vent that is plugged and permits a backflow of
water into the cylinders after shutting off the engine. The water, then,
seeps between the pistons and the cylinder walls into the sump.
Sometimes this problem, if not understood early, may cause the blow up
of the engine head at the next attempt to start the engine.

I second that. Also look in an exhaust system design flaw. Could the
seawater siphon back?

Jacques
http://bateau.com

Water is commonly found in engine crankcases where the engine is
run for short periods. Water vapour is a byproduct of combustion, and
as there's always a bit of combustion gas escaping past the rings into
the case, it will condense there and mix with the oil. The engine
needs to be run long enough to get the oil up to 180 degrees for a
half-hour or better to eliminate water that accumulated during a cold
run.
What's your block temp like? Too cool? Do you have an oil temp
gauge? Are you running the engine for a few minutes in the off-season
to "circulate the oil?" Bad deal.
Oil breaks down in the presence of water and metals, and forms
acids from the sulfur and chlorine compounds in the oil. Corrosion of
bearings and other stuff happens. It's what wrecks the engines in
older cars and aircraft that have low hours or miles on them: they
look good to a buyer, but the damage is inside, unseen. Trying to
convince people that short runs are bad is often impossible.

Dan

The same thing applies to fuel in the oil. 4-stroke motors need to run hot
for awhile to get rid of (vaporize) fuel that makes it past the rings and
into the oil. 4-stroke motors that are cooled by seawater rather than a
separate freshwater system are the most prone to this ...run them too hot
and the salt crystallizes in the galleys (must use a cooler thermostat) but
if they aren't run hot enough, then fuel ends up diluting the oil. This is
one of the best reasons to NOT have a seawater cooling system. A freshwater
system can allow the motor to run hotter, thereby vaporizing water and fuel
out of the oil, without crystallizing salt in the galleys.

Brian D



"Dan Thomas" wrote in message
om...
(Jacques) wrote in message
. com...
Daniel wrote in message
Ralph

Not so uncommon and may be due to a malfunctioning of the exhaust/raw
water discharge circuit.
Sometimes it is just a vent that is plugged and permits a backflow of
water into the cylinders after shutting off the engine. The water,
then,
seeps between the pistons and the cylinder walls into the sump.
Sometimes this problem, if not understood early, may cause the blow up
of the engine head at the next attempt to start the engine.

I second that. Also look in an exhaust system design flaw. Could the
seawater siphon back?

Jacques
http://bateau.com

Water is commonly found in engine crankcases where the engine is
run for short periods. Water vapour is a byproduct of combustion, and
as there's always a bit of combustion gas escaping past the rings into
the case, it will condense there and mix with the oil. The engine
needs to be run long enough to get the oil up to 180 degrees for a
half-hour or better to eliminate water that accumulated during a cold
run.
What's your block temp like? Too cool? Do you have an oil temp
gauge? Are you running the engine for a few minutes in the off-season
to "circulate the oil?" Bad deal.
Oil breaks down in the presence of water and metals, and forms
acids from the sulfur and chlorine compounds in the oil. Corrosion of
bearings and other stuff happens. It's what wrecks the engines in
older cars and aircraft that have low hours or miles on them: they
look good to a buyer, but the damage is inside, unseen. Trying to
convince people that short runs are bad is often impossible.

Dan

Jacques wrote:
Daniel wrote in message

Ralph

Not so uncommon and may be due to a malfunctioning of the exhaust/raw
water discharge circuit.
Sometimes it is just a vent that is plugged and permits a backflow of
water into the cylinders after shutting off the engine. The water, then,
seeps between the pistons and the cylinder walls into the sump.
Sometimes this problem, if not understood early, may cause the blow up
of the engine head at the next attempt to start the engine.


I second that. Also look in an exhaust system design flaw. Could the
seawater siphon back?

Jacques
http://bateau.com

Ralph,
this is exactely what I was trying to say but I missed the proper word
"siphon". In my engine there is a vent (actually a small copper tube
that goes overboard) in the highest point of the sal****er circuit
discharge, before the latter joins the water-cooled/wet part of the
exhaust. This vent avoids sal****er siphoning into an engine installed
below the waterline. And mind it: the siphoning is not through the
exhaust outlet that, usually, is out of the water, but the other way
round, through the sal****er pump and its inlet seacock.

Regarding moisture condensation in cold engines, this is mainly a
problem of muffler rusting in cars. What the starter of the thread had
in mind (and me too) was more than a quarter of water emulsioned with
oil in the sump. Something that makes you think: "gee, finally my
engine has stopped burning oil...!!!!"

Daniel