Uh-oh... Carmel colored oil

[Beave]

I was getting my grandpa's old Starcraft out today.

Something isn't right with the oil. It's a light brown "carmel" color, and the consistency isn't right. It isn't see-through on the dipstick anymore either. Has anyone seen this before?

Is this caused by water in the oil? This is an I/O. Ideas? Suggestions?

My first course of action is going to be changing the oil and filter (it was on the spring "to-do" list anyways), and seeing if the problem re-occurs. My grandpa normally pours some anti-freeze into the block as part of the winterization process. I'm wondering if he pulled the oil cap on the valve cover and added it there instead...? He's starting to make those kind of mistakes in his old age once in awhile. If that doesn't explain the problem all I can think is there may be a leak in the head gasket somewhere...?

Help me out. Re-building a boat engine wasn't something I wanted to have to do this spring.

[salmonslammer]

Run a compression check on it....if you have lower psi on 2 cylinders that are next to each other that would indicate a bad head gasket.

Did you put any of the oil in a glass jar to see if it seperates??


Sounds like a bad day regradless....

[FishTales]

Beave,
Does the oil look more like chocolate milk ?
Are you able to start it up and let it run ? If so run it for a couple of minutes then check to see if the oil looks like a milk shake, chocolate colored and foamy.
I had the same problem with and old (1964) Starcraft with Merc 110 I/O.
I had water in the oil, I was told before I bother replacing the motor to check the water jacket in the exhaust manifold.
What happens is the exhaust will eventually erode the aluminum plates used for the water jacket, then when you shut off your motor any cooling water in the jacket will leak back into the exhaust manifold and down though any open exhaust valve into the cylinder, from there is seeps past the rings and down to the oil pan.
If I remember correctly there should be 3 part for the exhaust manifold, it should be the center plate that will be worn through and have to be replaced.
Make sure you get a gasket kit before tearing it apart, so if thats not the problem at least you will have the gasket to put it back together .

[Burksee]

When was the oil last changed? Moisture/Condensation contracted over the winter might be all you've got. Moisture will show up easier in "newer/cleaner" oil than in "older/darker" stuff. I'd change the oil & filter, run it for a while and see what happens. You might not have anything wrong at all! Good Luck!

[Beave]

Yes, chocolate milk is another good description.

Exhaust manifold gasket in the water jacket sounds like a likely culprit too.

I'm changing the oil today or tomorrow and I'll see if the problem returns.

[Beave]

Bad news...

Compression on all four cylinders was 165-175 psi. That rules out a head gasket.

Now we're down to the exhaust manifold or a cracked block.

It's troubling since I know the boat was winterized properly. I fogged the cylinders, pulled the plug on the water jacket, and as an added precaution pulled one of the water hoses and poured some anti-freeze down in the water jacket. (The plug on this model is up on the side and doesn't drain all the water so we've always poured a little enviromentally safe anti-freeze in just to make sure there's no water hiding in there.)

I was originally thinking it's possible my grandpa went to do the anti-freeze trick himself and got the line from the head to the air filter. It's his boat so he likes to do stuff like that even if I've done it. The boat has been re-winterized in the past so it's to his liking.

At this point I really can't think of anything else it could be.

[7MM Magnum]

If it were me,... I'd do what burksee suggested. ;)

Change the oil & filter with fresh stuff,.. put a set of muffs on the water pickups of the motor and run it for a while and then check it again.

With the description of your oil it has been contaminated with water,.. no doubt about it. That chocolate milkshake crankcase fluid is not a nice thing to find at the beginning of a season. I hope it turns out to be nothing serious but it sounds like a motor tear down to me. :(

[FishTales]

Originally posted by Beave
My grandpa normally pours some anti-freeze into the block as part of the winterization process. I'm wondering if he pulled the oil cap on the valve cover and added it there instead...? He's starting to make those kind of mistakes in his old age once in awhile. If that doesn't explain the problem all I can think is there may be a leak in the head gasket somewhere...?
Beave, you make it sound like granpa is lucky to have you around, be nice to the old people, if your lucky you will be there some day. :D
In my previous post I mentioned if the water jacket has a hole in it the water will leak into the manifold when you shut it off.
If you decide to change the oil & filter, then run it with muffs on, when you stop the motor, leave the muffs on with the water running for a few minutes, if it is the manifold water jacket it will give it a chance for the water to get in.

[Joe_G]

I bought a boat that sat in a side yard for 10 years. Same oil color. Changed it and the filter, problem was solved for 10 bucks. I prefer to water test 'em submerged at a DNR launch. No worries there about connections & impeller damage & so on. If at all possible, due it very soon. You got maybe 3 weeks or a month before all heck breaks loose at the launches.

[fishin addiction]

I had a thermostat go bad and never got warm enough to burn out the moisture. Might want to try replacing that if all else stilldoesnt fix it. Nate/Fishin Addiction/