Yamaha F350 water in oil / milky oil

[rbhankins001]

2008 Yamaha F350 with 1160 hours on it.

Was laid up over the winter (in Alaska) properly winterized (i.e. fogged cylinders, stabilized fuel system, and stored in the down position inside a warehouse).

After running 1 hour I checked the oil and it was very milky. And level way over full mark on dipstick.

Motor was running perfectly, wouldn't have thought anything was wrong without seeing the oil.

Change oil and run about half an hour (mechanics thought t-stats stuck open in 45 degree water making condensation in crank case).

Same thing!

So shipped it to mechanic ($$$$$) and he basically says I need a new motor. That really isn't an option right now. He has not pulled heads, or really done much of anything. He did pull plugs as I requested a compression test. They look very bad (they looked like new ones at the end of last season). All covered with stuff (milky oil that's been burned??).

What to do and what to look at?

Is this motor DONE ? I really can't see how as it is still running.

Only other thing is that I know this motor very well and the exhaust sound was "slightly muffled" is how I would describe it.

And we are talking its going way up the dipstick, and quickly.

Thanks

-Rob

[99yam40]

Leakdown test might show something, but if mech does not want to check out what he can, I do not know how you are going to find out what is wrong.

Crack or corrosion could be the problem, but may take a tear down to find

[boats.net]

Would need to pull cylinder heads to see if has any water damage, pull exhaust manifolds and look for cracks inside manifold to allow water to enter exhaust valves.