496 Oil Question
 

Mine for some reason, turns the oil jet black only after 1 or more hours of use (not even wot). Started out using Merc 25/40 and then switched to Royal Purple 20/50. Tried changing it twice in a row only after about 8 hours each time and still gets very dark very quick.

It's seemingly way to dark to me but the motor runs perfect. Is it not a big deal?

Also, sent a sample to be analyzed. Came back with generic, vague report from Blackstone Labs in Indiana. Said it was fine with no abnormalities but they could not explain the dark color. Has to be carbon - no?

???????

Blowby causes blackness if it comes on that fast, are you sure you got all old oil from the engine out when you make the changes?

I´d measure your engines blowby, a compression test won´t suffice.

How are you changing your oil?
Which filter are you using? (I recommend the Napa Wix Racing 51060R; best filter out there.)

Advisable method is warm you engine up to suspend all dirt particles in the oil, (so not resting on engine parts); and to thin the oil for faster draining.

Then, pop a hole in the top of the oil filter with a screwdriver, which will allow all of the oil in the filter to drain back to the pan.

Then, use the oil drain tube, and let it drain overnight. Make sure you boat is tilted nose up on the trailer, or wherever you have it sitting. The oil drain tube is at the back center of the pan, so make sure you have the boat level side to side, and nose pointed up; to alleviate any (dark/old) oil sitting in the pan.

Sucking oil out the dipstick tube is NOT the preferred oil change method for ANY motor.

Sydwayz - popping a hole in the filter is definatlely the wrong way - all you have to do is loosen it just beyond where the rubber gasket makes contact so air can get into the filter as the oil drains down - no mess at all and no ripping metal. Yes the engine should be warmed up to suspend the dirt particles and to thin the oil. Where did you get the idea that sucking it out of the dipstick was not the perfererd method? Boaters have been doing it for decades and I am still using my Jabsco electric pump even though I have the drain tubes. The motors take 9 quarts with a filter and that is what I put in and it takes me right back to the full mark so I must be pulling 9 quarts out through the dip stick. I dont think that the oil turning dark after 8 hours is an issue. Does it look black on the dipstick or is it black on the paper towel when you wipe the dipstick? Is it burning any oil? What is the oil temperature it is running at 3500, 3800 and WOT?

Poking a hole or lossening the filter is acceptable by me. I can't use the dipstick method. Motor is too close to bulkhead. Instead, level the boat, tilt up not much because the drain hose is located almost center of pan so too high and you're leaving a lot of old oil in... Simply pull the drain hose through the bilge drain hole and use a fluid extractor. Works very well and no need to drain overnight. REGARDLESS of how you drain the oil, you will NEVER get it all. I get out everything I put in so I got that down.

There was a question about filter-- first, used Merc filter, then Napa Gold 1060 (slightly larger), and might try the heavy duty Donaldson just to see. Westcoast suggested a K@N. Maybe that one too but no filter will affect dark coloring that much. This is probably just a characteristic of this engine but I sure appreciate everyones input.

Sydwayz,

Just curious why you say that sucking it out of dipstick is not good for any motor??? Marinized engines (most of them) have the dipstick tube that goes all the way to bottom center of the pan only leaving maybe an inch away from dead bottom of pan... If you've ever looked at most oil pans on our trucks, even when put on a rack and draining by removing the drain plug, you still don't get all oil out. With due respect, isn't this all pretty much the same thing minus a few drops that could not possibly matter much??

Sydwayz is correct. Sucking oil out of the dipstick leaves almost a quart of dirty oil in the pan. It is worth the $20 to get drain hoses. (Which is when you'll find out how much oil is left in the pan).

dip stick is not efficient enough at removing all the oil. drain hose is. i myself use the hole in filter method. however i usually run the engine or boat. after its good and warm, shut it down. come back an hour later and suck out the old oil.
we service about 20 496's a week, maybe a little less, and this has been proven to be most effective at removing as much old oil as possible.

just a question, does the oil smell like fuel? i have had a couple of engines come in with black oil.

If you use the Napa/Wix Racing Filter as I do; with the anti-drain back valve, loosening the filter does not work. You have to puncture it at the top dead center. Also, I have found that if you loosen the filter enough to get air in, you are going to get oil out, and I don't like the mess.

The filter trick was taught to me by one of the best marine mechanics I have ever met; as such I believe him. (Pwrbt33 here on OSO.) I have a specific screwdriver optimized for the task. It is the perfect length to go all the way through the filter, yet not past the filter. I have it sharpened to a blunt point at the end. Works great.

Think of how big the bottom surface area of your oil pan is. Then think of how much volume of oil that is; just 1" tall. That's is EASILY a quart.

Your 496 should have come with the pan drain tube installed from the factory. Its the ONLY way to go. So much so, that I installed it on my old 500EFI. I sucked all of the oil out via the dipstick tube, and then pulled the drain plug to install the tube. I still had at LEAST a quart drain out into my bilge. Talk about a black ugly mess!!

BTW, my PSD Ford has the oil drain plug on the very bottom center of the pan, and the pan tapers down from the 4 corners; as such I am sure that I get all of the oil out; less just a smidgen left from the ridges of the threads of the hole.

Well then,

There you have it. I stand corrected. After spending a considerable amount of time inspecting the locations of both, the dipstick tube and the drain hose, they "seemed" to be the same height from the bottom of the oil pan from what I could see.

thanks a lot guys!
jason

Sydwayz, Didn't you have your ECU's sent in for that free Merc upgrade last year to lean them out alittle to eliminate how rich the early ones ran? Just a guess but I would say that everyone getting alot of soot on the transom also is having the oil darken quickly. Did you have the problem before and did it clean it up after the reflash? I think you had a thread on this a while back?

I just pulled my plugs and they are as lean as they can safely be... I thought the same thing about 3 days after I started this thread. It's just one of those things that really isn't hurting anything but it annoys you when you pay 6.69 per quart.

If there is a re-flash that leans it out, I would certainly not be needing it but I still have the transom soot. got over that a while back...

turnerrd is correct. There is a technical bulletin or whatever from Mercury on the 496s. The early ones were set pretty rich. I got my ECUs replaced under my warranty coverage via this new program. As it turns out, it was better for my ECUs to be replaced vs. re-flashed, and this was Mercury's decision.

It definitely did 'brighten' my transom!

snapontoolsjt, if you contact your local Mercury dealer with your engine SN and the SN of your ECU, they can tell you what you may/may not need done.

black oil
 

hey monstaaa you said that some of the fountains you have worked on have black oil.i too am having the same problem.have changed oil 3 times just this year and still have the same black oil.i am wondering if my oil temp is too hot.it runs about 240.too hot?

It's tough to read plugs on the 496 as it has an individual coil for each cylinder. This makes it burn hotter especially at idle and thats probly where you are checking them so the plugs will never really look fat always lean. Excessive soot on the transom definatly means rich though.
Sydwayz, didn't you recall a couple of guys saing they lost speed and RPM after the reflash? Did you see that with your new ECU's? I'm thinking about sending mine, but thats what stopped me at first.

Rob

I hit my best top speed ever before the ECU's were replaced with the leaner program. The boat had none of my usual gear on it, and was nearly empty on fuel.

I have never tried that again on my boat, and have actually added weight with subwoofers, amps, and other things. I don't go boating to squeeze out an extra .763421C87 mph. I like reliability and longevity, hence my extended warranties until 2010.

I do think a few other folks may have mentioned loosing a few ticks.

I'd have to say the dark oil is caused by a slight rich condition that produces the carbon (black). It's not like it's raw fuel thats getting into the oil. Just not completly combusted. Given the choice to be a little rich or little lean? Not a tough decision. It would be nice if someones whos in the know specifically on the 496 could chime in here.

Ran into a 496 torn apart this morning. noticed that the drain hose (port side) and the dipstick tube (starboard) are in relatively the same center location of the oil pan on their respective sides. called mercury to ask about recomended way to remove the "most" oil from this particular engine.

as I orginally assumed, they are both equal. they are both physically located at same depth in pan etc... they both remove the same amount of oil.

after carefully looking at the overall picture, one would actually leave MORE oil in the pan by raising the bow of the boat in the air much past level state. however, if this is done, it would net a very minor residual drip drip overnight as some have suggested. either way this is not the issue.

how are you changing your oil? and what is your procedure. and 240 is hot but not too hot, unless your reading is wrong or it contaminated