Black Exhaust Goop question Johnson 90HP OceanPro

[cprodave]

I have a 2001 Johnson OceanPro 90HP 2-stroke that drips a black goopy ooze after I run it. Engine has maybe 600-700 hours on it?not a lot for the year (no HourMeter). This happens regardless of whether I run it for several hours or even if I run it (with flushing muffs/running water) on the trailer for 5-15 minutes. The amount of ooze depends on how long I run the engine. If I run it for 10-15 minutes it makes a couple ?shot glasses? (maybe 2 liquid ounces?) of black goop. If I run it for several hours out on the water (ocean?saltwater) , then put it back on the trailer and flush with flushing muffs, it produces more?I would guess maybe 4 ounces (that drips out over a period of several days). The black ooze comes out of the center of the prop and also from behind the prop ?I will try to post photos tomorrow (this outboard has through-the-prop exhaust, of course. And it automatically mixes oil into gas). Sometimes I run non-ethanol gas but mostly I run E10. I have used several brands of oil (including Evinrude/Johnson 2stroke Premium) and see no difference in ooze production. The black ooze does not appear to be coming from Lower Unit lubricant?I removed the top filler hole in the Lower Unit and a bit of lubricant spurted out?so I know that the Lower Unit lubricant is not being consumed/depleted to form the black ooze. I have 4 other small outboards (3.5 to 6HP) and they all leak a bit of combustion oil, but not nearly as much as this 90HP outboard. This outboard has been dripping this ooze for at least 3 years and thus far I have seen no harmful effects. Overall this outboard does not smoke much (for a 2 stroke) and in fact one of my most knowledgeable boating friends (40-50 years with outboards) feels that this engine smokes very little. There is no fouling of sparkplugs?they burn a nice tan color and get replaced every 3 years or so.
The boat seems to have plenty of power?as much as I ever remember it having (although over the 15 years I have owned this boat I have not kept good GPS-quality records of speed at various RPM?s). So I don?t think a cylinder (or 2) is (are) not firing. But I understand cylinder(s) not firing could be the problem?with powerpack or shift interrupter switch often being the root cause. A couple years back I had 1 cylinder not firing and as I recall there was a noticeable loss of top end power/speed.
I am taking my boat to get a non-engine-related problem fixed this week, and would like any ideas/input you might have so that I can discuss this ooze condition (I?ll avoid calling it a ?problem?) further with my mechanic. Thanks

 

[ondarvr]

Normal, some oils and some motors do it more than others, it can increase if the thermostats don't allow the motor to get up to the correct temperature, or if the motor is running rich.

 

[cprodave]

Thanks ondarvr for this input...very helpful, gives me hope that I'm not headed for a whopper repair bill...

 

[Fishnfool1957]

I have the exact motor and am experiencing the same "problem". Please let me know if you find a solution.

 

[crazy charlie]

Have you ever done a decarb??When I do a decarb, that is typically when I see what you are describing.A little in the following weeks after the decarb but not as much as you are describing.Charlie

 

[cprodave]

Fishnfool, interesting that you have same condition. Yes I will let you know after my mechanic looks at it (I am on his schedule for 4/21--so will let you know around 4/24 or 4/25.

Crazy Charlie, no I have never done a decarb, at least if I am understanding what you mean by decarb. Do you mean something like SeaFoam treatment, or more involved like removing the heads and scraping off pistons etc? Please advise.

Thanks folks for continued input.

 

[crazy charlie]

Do a search on "decarb procedure" here.It is very simple and yes Seafoam is a good way to do it.In short,on a warm motor spray Seafoam in carbs similar to fogging the motor.Try to keep it running for a little while while spraying into the carbs and then stall or shut motor.Tilt motor up and pull plugs.Spray seafoam into each cylinder.Put plugs back in and let sit for at least half hour.Start motor and take it for an aggressive ride.You can repeat this procedure .If you have never decarbed before ,you are gonna get a lot of black crap coming out exhaust.You can also let fuel run low and add a healthy dose of Seafoam so fuel is concentrated and will clean while running.This procedure can actually raise compression and if you get decarbed good enough may eliminate the black crap coming out exhaust.BTW gonna make a lot of smoke!! Charlie

 

[jjacobs007]

I would check the lower unit seals by prop they might be letting oil pass by when running under pressure and check oil and see if it's milky too. This was my problem on a 1970 Johnson 60hp once

 

[ondarvr]

The goo is a combination of combustion byproducts and water, they get mixed together in the exhaust housing and form a viscous sludge that clings to the inside of the housing. Over time the water/oil mix starts to separate and the black oily sludge starts to drip down onto the clean floor under the motor and forms a nice black oily blob, it may start out a bit brown or milky in color, but as the water evaporates it will turn black. This goo won't have a strong odor, but may smell a little like fuel or plain oil, gear oil from the lower unit will have strong odor.

​It's more likely for the sludge to form if the motor doesn't get up to full operating temperature, and some oils tend to form this sludge more than others, the faster an oil disperses in water the less of it you will see, this doesn't mean it's a cleaner oil, just that it mixes with water easier.

 

[cprodave]

Thanks to all for the additional input. I am scheduled with my mechanic on 4/21 so by 4/25 I should be able to provide an update in this forum.

 

[clemsonfor]

Yep it's normal. If you have extra oil or do a lot of idling you will get that nasty goop that runs out. Pretty normal though.

 

[cprodave]

Thanks clemsonfor, good to know I do not have an unusual (for this motor) condition.

 

[boobie]

If you want to do a good de-carb on it go to any BRP dealer and get a can or two of Engine Tuner. Follow the directions on the can to a "T". I've had good luck with it.

 

[boobie]

Another thing to check is that the mtr is coming up to proper operating temperature at idle and WOT.

 

[clemsonfor]

Black goo or black goop should be a sticky, haha. It is asked pretty frequent!

 

[cprodave]

Hi All, as promised I took my boat to my mechanic today and he indicated this black goop is quite normal especially if trolling a lot at low speed, running at idle with flushing muffs on while on trailer. etc. He mentioned that on his own personal boat he has twin OMC motors (not sure if Johnson or Evinrude)--one motor produces the black goop and the other motor does not! Go figure...anyhow, all is well. Thanks for your inputs.

 

[crazy charlie]

Fishnfool, interesting that you have same condition. Yes I will let you know after my mechanic looks at it (I am on his schedule for 4/21--so will let you know around 4/24 or 4/25.

Crazy Charlie, no I have never done a decarb, .

So based on your mechanic telling you all is good you are still not going to do a decarb???? Big mistake.....

 

[cprodave]

Charlie, if I were going to keep this boat with 90HP Johnson then I would do the decarb..but pretty sure the boat is sold (based on excellent results on Compression Test performed last week). I am downsizing to keep just a smaller skiff (plus 3 kayaks and a canoe) and I have 4 outboards to keep up-and-running for the skiff. However, the new owner might want to do the decarb on the 90hp Johnson. Thanks for your input...