Evinrude 9.9 leaking oil

[DeanHensler]

I just picked up a 1992 evinrude 9.9. It had been sitting for a while before I bought it. The guy I bought it from ran it in a tank for me so that I could see it run. The thing ran perfect in neutral, forward and reverse.

I brought it home and put it on a stand. After sitting for a few hours I see its leaking a BLACK oily substance. The leak is at the front of the prop where the prop meets the lower unit housing.

I read on Leroy's Ramblings that these engines push the exhaust through the prop and can leak about black oily substance out the prop if they've been sitting a while (mixture of exhaust and carbon build up causing it to be black). This would all make perfect sense, but it isn't leaking out the center of the prop but rather the front of the prop where it meets the lower unit housing.

Is this normal or something to be concerned about?

I've attached a picture to point out where the oil is leaking from. This is not an actual picture of my motor.

 

[DeanHensler]

Re: Evinrude 9.9 leaking oil

Here is a more close up picture of where the motor is leaking. This is not an actual picture of my motor.

 

[nwcove]

Re: Evinrude 9.9 leaking oil

all depends on how the motor is tilted when its on your boat/stand. more than likely perfectly normal. but its normal routine maintenance to check and change the gear oil on any newly acquired outboard. ( make sure to replace the drain and fill washers/orings if you do change and inspect the gear oil)

 

[the machinist]

Re: Evinrude 9.9 leaking oil

As NWC says, same oil, just different motor position. The prop does no have a seal around the housing, so any unburned oil will also leak out as in your situation.

 

[DeanHensler]

Re: Evinrude 9.9 leaking oil

What kind of oil does this thing take and what is the procedure for changing it? I understand you have to fill it from the bottom up. Is there an inexpensive manual pump I can buy for this?

 

[popsmazz1]

Re: Evinrude 9.9 leaking oil

yes, you can get one at an auto parts store, has a fitting that srews into the gear case at one end, the other end screws on a quart bottle. take both fill and vent screw out let it drain and fill from the bottom up. 90w gear oil.

 

[Putzaroni1]

Re: Evinrude 9.9 leaking oil

As NWC says, same oil, just different motor position. The prop does no have a seal around the housing, so any unburned oil will also leak out as in your situation.

I've got an 1983 Johnson 9.9 that is doing the same thing. It was fine last year when I put it away but I pulled the lower unit off, did the impeller and cleaned it all up, put it back together, changed the leg oil and fired it up. It ran great, shifted perfect but when I pulled it out of the tank there was golden colored oil mixed with water.

Could it be something to do with how I put the prop back on ? I know it leaked a bit before but now it's leaking pretty heavy and with water coming out as well I'm afraid !!

Could it be that I need to tighten down the prop shaft nut more ? I thought it might be the prop shaft seal but it looks pretty good. What are my next steps to resolve this ? This motor needs to going fishing.......

Any suggestions appreciated and needed.

 

[Rick.]

Re: Evinrude 9.9 leaking oil

Don't over tighten the prop shaft nut. That will not be the problem but will be another potential problem if over tightened. You should crack the drain/fill screw at the bottom of the gear case (slotted screw) and see what comes out. If water is in there it will come first unless its mixed with the gear oil in which case the oil will look milky. Often times the water intrusion is caused by the nylon crush washers not being replaced when changing the gear oil. So, my next step would be to change out the contaminated oil with new crush washers and then monitor the oil during the summer. Unless it gets really bad fast I would fish. In the winter I would put a new seal kit in the gear case. Best of luck. Rick.

 

[Putzaroni1]

Re: Evinrude 9.9 leaking oil

Thanks Rick,
I cracked the bottom drain plug and what looked to be new oil came out, not at all diluted or oily. I only ran it in the tank for about 10 mins though so maybe it didn't have time to get enough water in there to be obvious. How long would it need to run in the tank before it would be obvious that there is water in the oil ? I only ran it the once but there was fair bit of oil coming out from the back of the prop between the prop and the lower unit housing. I'll try running it on the weekend and see if there is any difference.

 

[Rick.]

Re: Evinrude 9.9 leaking oil

Sure sounds to me that your fine. If your gear case was leaking it would of course depend on the severity of the leak as to how quickly it would contaminate the gear oil. When running, the motor always produces unburned gas/oil mix into the exhaust. I think that is what your seeing and very normal. On the water at higher rpm that tends to get blown out with the exhaust and you will notice less of it after use (unless you troll all day0. At the end of the day I always try to go full throttle even for a few minutes to clean out the unburned mix and heat things up a bit. Cleans the plugs too. Get fishing. Rick.

 

[Putzaroni1]

Re: Evinrude 9.9 leaking oil

Update:
So I pulled the motor out, replaced the drain plug washers top and bottom, put it in a garbage can and ran the motor for about 15 mins. I noticed some tan colored globs of something floating on the surface of the water. I shut it off, wiped off the lower unit, dumped the water and filled it again. I started the motor, ran it for probably 20 mins in drive at trolling speed. The water looked better. The lower unit was dirty with residue not too bad. I wiped it off and tried running it with muffs. In the prop there is a a milky looking blackish goo that was mixed with water. I have seen that on other motors but am not sure how much is OK. I wiped it all down and no more has shown up while it's sitting on the stand. I cracked the bottom drain plug on the lower unit and it looks to be clean. With the motor having run in a garbage can I would think there would be some goo as it is a 2 stroke and there is no where for the residue to go. I also put Lithium grease on the prop shaft when I serviced it so that could be part of it.

Does that sound about right still or should I be digging deeper ?
Thanks again so much.

 

[JDusza]

Re: Evinrude 9.9 leaking oil

Why not be sure the lower unit is full and then run it for a while. Then recheck oil level.
Running in a can will always give you goo.
Fill it, run it, check it.
J

 

[Putzaroni1]

Re: Evinrude 9.9 leaking oil

Just an update on this.
So I took the motor out to the nearest lake for a run and it did run well. Once I was finished running it I had a look at the prop housing and there was no sign of any goo or anything else there. I looked again the next day and still nothing so it looks like Rick was correct (never doubted him for a minute) !!
I write this because there was a fair bit of goo showing after running it in a tank and I was thinking I was into prop or gearshaft seals but apparently there is no need ! The water in a tank gets pretty ugly fast as everything is exhausted into it. There is going to be residue on even a newer 2 stroke after running it in a can.

Thank you Rick and others for being so helpful !

 

[Rick.]

Re: Evinrude 9.9 leaking oil

Well your welcome. Glad to hear good news. You think your 9.9 makes gunk. My 73 - 9.5 produced it twice or 3 times as bad. Almost everything I've learned about outboards has been learned by the many contributors of this forum. Some of the hardest lessons have been learned on my own. We are all very fortunate to have this forum available to us. Thousands of outboards are earning their keep that without this forum would be sitting quietly collecting dust. Fishing opens here on May the 8th. Hope you've been having some luck. Rick.