Looks like the launch of the new boat may be delayed a bit. I was going through the boat today, and one of the things I did was check the oil.

Starboard engine is fine, right on the full mark. Port engine, however, is another story. The dipstick shows well above full, and the oil is a lighter brown, chocolate milk color. Looks to me like I've got oil in the water on the port side.

Now that being the case, both motors have started and run fine on the hose. Obviously, I won't be starting the port motor again until I can change the oil, but can I get some ideas on A) what could cause water to get in there, B) how to fix A, and C) what sort of damage may have occurred up until now (hopefully none!).

Many thanks - I had forgotten just how much fun a boat can be...

Exhaust manifold leak

Intake manifold and or gasket leaking

Pull the thermostat housing and look for a hole under the t-stat.

Worst case,cracked block from freeze? Prob just head gasket or intake gasket leak,,intake more common and the place to start. Doubt you did damage by running that way a little,,,until it gets really milky it's mostly oil. Have heard bad reversion can do this over time. Can you pull the distrib and pressure up your water jackets and peak in the intake to look for a drip. Might could borrow a scope?if it's not coming from the valley pull the heads next and look for gasket failure,,if not t(here,,,do all your plugs look good?no water?)block is cracked? My .02 Good luck. Guess your heads could be cracked or corroded thru as well.

I had the exact same problem once. Ended up being Exhaust Riser Gasket. If you had a crack it will fill the crankcase with water fast. LIke stated in a prev post, it only takes a little water to make milkshake. I found my problem by taking off the ebow on top of the exhaust and you could see where the water was dripping back into the exhaust.
Good Luck, better now than the middle of summer

Hey Dock,
It would be a real good idea to get that oil out of there pronto and change it before it does any damage. Do it with cheap oil because you will be doing it again as soon as you find the problem and fix it!

Trust me on this, I've been there!!!!


Craig

I'm betting it's an exhaust gasket - I have had a feeling that something ain't quite right on that side. That being the case, I'm nowhere near a mechanical guru, I'm wondering if I should just shop this out...

That sux! I just bought a boat this winter and lost a motor on it's maiden voyage. Mechanic has it now doing a complete rebuild dropped a valve and blew it out the motor) Sounds like you might get it fixed for hundreds instead of thousands. Good Luck

OK boys, I just looked under the hatch. There's this big black hunk of metal, with gizmos and widget bolted all over it. Says "Mercruiser" on it. Which thingamabob should I unhook first?

In all seriousness, I'm not that clueless, but close. I'm willing to have a go at this, and I'll even document it - maybe we could sticky a thread or something for other noobs like me.

Now for some visual aids.

The guilty party (or the victim, depending on how you look at it) - a 1996 7.4 LX MPI, approximately 400 hours.

Next question, I can see where the exhaust risers (or elbows) attach to the manifolds. Should I take these off? And if so, what should I be looking for?

Also, this gizmo blocks one of the four bolts holding the elbow in place. What is it, and any suggestions on how to reach that bolt?