Port motor oil black after 35 hours of run time

[Patriot]

1996 Crusader engine runs fine. Had the oil changed 2 times, 2 weeks apart 3 weeks ago and the oil is black again after 35 hours of run/troll time. Oil pressure is fine. Starboard engine oil appears fine. Suggestions?

[Xxx]

Is this the first time this has happened. Have you changed oil before and they were the same? Meaning one engine might be rebuilt and not the other? If not does each engine have its own temp gauge. Usually there are 2 major things that turn oil black quickly, excessive heat or lots of carbon like unburned fuel or a weak cylinder where the carbons of unburned fuel or the gasses of unburned fuel mix with the oil. Sometimes a simple tune up can cure this issue. If the oil doesn't smell like gas its contaminated with carbons, and if it is thicker than its a over heating issue. Some places can check your oil to see what's in the oil. Like a heavy duty truck repair or a dealership, usually a Diesel engine repair shop, they are always concerned with the longevity of oil. Just some food for thought.

Edited September 5, 2015 by pap

[Patriot]

Thanks for the suggestions Pap!. I just bought the boat last fall and this was the first oil change as we haven't used the boat very much, under 60 hours. The engine is running about 10 degrees more than the other engine but I have a feeling it might be unburned fuel and I believe its running a bit rich, when I start, it throws a bit of gas from the exhaust. I'm going to have my mechanic do a tune-up, see what happens

 

Thanks again

 

Greg

[Xxx]

Thanks for the suggestions Pap!. I just bought the boat last fall and this was the first oil change as we haven't used the boat very much, under 60 hours. The engine is running about 10 degrees more than the other engine but I have a feeling it might be unburned fuel and I believe its running a bit rich, when I start, it throws a bit of gas from the exhaust. I'm going to have my mechanic do a tune-up, see what happens

 

Thanks again

 

Greg

Good idea, especially if you think there is raw fuel being spewed out the exhaust. You are very welcome, best of luck with your new ride.

[Knotlost]

You need to do a simple compression check. That will tell you a lot very quick and cheap. I'm betting you have a cyl that's broke rings out.

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PKomrowski

[Patriot]

Good idea.

Thanks

[RSF]

Ditto Knotlost. Compression test. First Dry, then Wet. Note each plug condition while performing the Comp test.

[lakebound88]

What was your conclusion and brand oil?

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[Patriot]

I haven't heard anything yet