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Oil turned black after 5 hours on water

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Oil turned black after 5 hours on water

Old 06-08-2011, 04:59 AM
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Default Oil turned black after 5 hours on water

I am a first time boater. Mine is a Key Largo 22 CC and it has a 2002 F200 with 325 hours when I got i 3 weeks ago. I did a complete tune up myself before took it out last weekend. New plugs, engine oil, low unit oil... We went out about 35 miles with RPM average around 4K. I drained the engine oil afterward and it looked like car engine oil with 3-4K miles. The engine performed flawlessly. It idled smoothly without any abnormal noise while running. Is this normal? .
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Old 06-08-2011, 05:06 AM
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Most probably it didnt drain all the old oil out, so you now are looking at a mix of fresh and old oil. If you read a few posts here, you will see that the motor needs to be warm, trimmed up and then down..and then drained. But virtually impossible to remove all of the old oil, unless left draining for some time.
Also, dont reuse those lower unit drain screw gaskets, as well as the gasket on the motor oil drain needs to be replaced regularly.
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Old 06-08-2011, 05:08 AM
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I tend to agree.......change it again (gues you were since you drained it) and check it after a couple more hours.
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Old 06-08-2011, 05:53 AM
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The engine takes about 6 quarts. I drained more than 5.5 out the first time with a new filter. Can ~0.5 quart turned the rest black?
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Old 06-08-2011, 06:02 AM
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Oil turns black quick. A lot of mechanics say it is better to have a little less oil than too much oil in these engines. They suggest 5.5 qts, not 6 per engine.
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Old 06-08-2011, 06:10 AM
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It tells me your detergents are working. Which is what you want.
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Old 06-08-2011, 06:11 AM
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Or, motor could have been over due for oil change? Fresh oil just picked up some of the gunk in there and broke it loose? Change it again and keep an eye on it, enjoy the boat. Don't panic.
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Old 06-08-2011, 06:22 AM
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If you don't like premature black engine oil here is a little trick I do when I change the oil in my diesel truck. Pull the plug and let it drain until it is just a drip. Without putting the drain plug back in add a 1/4 to 1/2 quart of fresh oil and let it drain again. Still not a 100% but will flush out a lot of the remnant dirty oil in most cases.

I just keep an extra quart bottle handy and use it for the "flush" only. Obviously it will last 3-4 oil changes so the extra expense is negligible in my book. Much cheaper then changing all your oil early.
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Old 06-08-2011, 06:31 AM
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Once oil flushes through your motor, it will turn black. Don't worry about it. The oil is fine.
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Old 06-08-2011, 07:07 AM
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Contrary to what some posters are saying here, I have found out that oil DOES NOT turn black before 60 or so hours of use (assuming all oil has been removed).
It will stay dark yellow for about 30 hrs then progressively turn brown, dark brown and black.
One more thing: Are you using Ring Free? If you dont, do.
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Old 06-08-2011, 07:41 AM
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I did not use ring free for the first tank but I'll start now. The boat sat for more than a year before I bought it. I will change the oil after going out for the next couple of times and see. What can cause the oil to turn black so fast? blow by? I guess I will do a pressure check for each cylinder and see. The engine idled so quiet that you cannot tell that it's on. One more thing, there is no smoke coming out on either hot or cold engine. Could it possible that since the cylinder is on its side even with worn rings and valves you still don't see smoke? And the old plugs that I took out looked normal (no heavy carbon deposit).

Last edited by green22cc; 06-08-2011 at 07:57 AM.
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Old 06-08-2011, 08:49 AM
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2008 DF-250. Changing the oil every 6 mo/50 hours and the stuff has always come out clean and light colored. My 400 hour service is coming up and I may have gone a but longer but I have never seen black oil come out of my outboard. (car, yes)
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Old 06-08-2011, 08:51 AM
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Originally Posted by go fish View Post
Oil turns black quick. A lot of mechanics say it is better to have a little less oil than too much oil in these engines. They suggest 5.5 qts, not 6 per engine.
x2
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Old 06-08-2011, 09:20 AM
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I want to know why you drained your new oil with only 5 hours on it? Now you're going to do that again the next couple of times you use the boat? Seriously your motor is running fine. Don't worry about it. Dark oil doesn't mean it is not in good shape. If you are really concerned, I would pull a small sample and send to Blackstone Laboratories for an oil analysis. They will tell you exactly what is going on with your oil. No guessing. And no changing the oil every time you use the boat.
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Old 06-08-2011, 10:46 AM
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I drained the oil after 5 hours because I just bought it and I just want to see if there is anything I missed when I bought it. The guy who I bought it from said there was no problem with the engine for the time that he owned it but I just want to be careful. I don't plan to change the oil after every trip. Just the next couple of times to see if the degradation will slow down once I get rid of all the sludge which some had suggested.
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Old 08-20-2011, 09:06 PM
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Just to follow up here. I finally log about 20 more hours on the engine since my last post. I check the oil every 5 hours or so. Happy to report that the oil color still somewhat gold in color. I guess some sludge remained after my first oil change when I bought the boat from the previous owner just like some of you suggested. Thanks for all the inputs.
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Old 08-20-2011, 10:22 PM
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Originally Posted by green22cc View Post
Just to follow up here. I finally log about 20 more hours on the engine since my last post. I check the oil every 5 hours or so. Happy to report that the oil color still somewhat gold in color. I guess some sludge remained after my first oil change when I bought the boat from the previous owner just like some of you suggested. Thanks for all the inputs.
Sorry I didn't see this thread till now, but oil is cheap. Anyone buying a 4 stroke outboard I recommend two quick oil changes in the first 25hrs they own the engine. The first one with a pint of Seafoam. Seafoam will clean the crankcase. Run it 10-15hrs with the Seafoam. SF does thin the oil some, so you don't want it in there permanently. But it never hurts to do a double oil change 10-15hrs apart every 200hrs on these 4 stroke outboards. Even if you use the cheapest oil with the engine manuf's recommended viscosity you can find at an auto parts store for the 10hrs it will flush the crankcase.
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Old 08-21-2011, 06:27 AM
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Has anyone heard of rinsing the crankcase with a few quarts of kerosene before putting in new oil? - I have heard it as an urban legend on motorcycles but have no idea if it's good or bad - Opinions experts?
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Old 08-21-2011, 07:29 AM
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Glen,
I would add SF or Marvel Mystery Oil to my oil before doing that JMHO...
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Old 08-21-2011, 07:39 AM
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Originally Posted by Cracker View Post
Glen,
I would add SF or Marvel Mystery Oil to my oil before doing that JMHO...
Both are good products to use

I have seen MMO bring back compression on 2 strokes. 80 back to 110+++
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