Thanks,

The pistons all had the same shade of black with none of them resembling
what you described. Black with no rust or water marks is all I saw. I wasn't
sure on this model if the water pump was isolated from the oil system or
not. Thanks for that info. The pistons are still in the block, as I have
torn down only the top part of the engine while it is still inside the boat.
I wanted to save the block removal for last in the event that no one finds
anything wrong with the top part of the engine. Looking at the exposed
cylinder walls, I see no visible cracks. I have not rotated the engine by
hand yet to check the rest, but will soon.

The engine is still apart, and I had checked the components for signs of
water marks in the exhaust and intake manifolds. They were all about the
same in color, with no marks of rust anywhere. Prior to dismantling the
engine after I took it off the lake, I ran a hot compression test. All the
cylinders were within the book tolerance. The heads looked clean too, with
no traces of water leakage around any of the gaskets. It is leading me to
believe that the block may have a crack. The engine ran fairly well too.

I live near Austin Texas, and the boat remains outside all year. It hardly
ever drops cold enough to be worried about freezing. As far as I know, the
engine has never overheated either. It has always ran around 160 degrees. I
never run it out of the lake unless I have a water system cooling the
engine.

I will take the heads, manifolds and risers down and let a machine shop go
over them. I'm afraid they may find nothing wrong, then what? Block??

BTW - This engine is a 1993 model. OMC Cobra. Kicks ass when it is running
good.

Dave

"Lawrence James" wrote in message
news
Do any of the piston tops look particularly clean? If water is getting in
through the combustion chamber or exhaust manifolds the water will often
scour the top of some of the pistons real clean. It is unusual for the
head
gaskets to just leak between the water and oil passages. Usually they
blow
out from the combustion chamber. I'm guessing it's pretty old since it's
a
351. Is it possible it froze last winter? Did it over heat badly at any
time? You can check the heads and block surface with a good steel
straight
edge. I use one of those steel drafting rulers.

Water pump can not get water in the oil. The block, heads, head gasket,
and
intake gasket are the only places that water and oil passages are in
proximity to each other. Water can also leak into the exhaust manifolds
or
risers, then run down into the cylinders. There it will leak past the
ring
gaps to the oil pan. Usually there are signs of water inside the exhaust
or
in the cylinders. Cracks in the block will be on the insides of the
cylinder banks if the water is getting in the oil. That is the only place
there is water in the block. They are usually not too hard to spot on a
disassembled engine.


"DMU" wrote in message
...
I have a 93 model OMC (Cobra) IO. 5.8 Liter (351) Ford...
I have an issue with water emulsion. I have taken the heads off,
exhaust,
intake and
even though there is water all over, there is no direct indication that
the
head gaskets
are blown or any of the top engine components being damaged. Except for
the
possibility of a cracked block, does anyone else have a idea how the
water
could
be getting in? Is the water pump a suspect?

Any help at all would be appreciated.

Dave