Black Oil Coming Out By Prop....HELP!!!

[Imtrying]

Ok, You super wrench's...I need help, and a cure for my 1974 70hp Johnson...I have a oil leak coming out down by the prop. The oil is black, and takes a few days to leak down to that point. I have been out with the motor about 5 times, and changed the oil in the lower unit a few times because I rebuilt the lower unit this winter, Making sure there is no water in the lower unit. There is a little water in the oil, and a little milky. I took the lower unit off today and see no oil leaks around the water pump housing, or the shift leaver housing. HOWEVER, shining a flashlight up the exhaust housing, I see black oil, that as I said earlier, creaps its way down to the exhaust down by the prop. (takes a couple of days to leak) Do I have a major problem? The motor runs fine, starts right up, 5200 rpm...35mph pushing a 900lb starcraft. Spark plugs are clean. LIke I said I don't see any oil leaks around the oil seals by the water pump, drive shaft, shift rod cover, or the oil seals around the bearing housing shaft that hooks up to the prop. HELP!!! Thanks, Dan

 

[rickdb1boat]

Re: Black Oil Coming Out By Prop....HELP!!!

Did you replace the seals on the lower unit screws when you changed the oil? Try that and see if it's still getting water in it. Otherwise, rub some of the leaking oil between your fingers and give it a sniff and see if it smells like oil/fuel. If so, it's unburned exhaust oil/fuel mix nad nothing major..

 

[Imtrying]

Re: Black Oil Coming Out By Prop....HELP!!!

rickdb1boat...Just went out to "smell" the oil, I've got a little cold, so my smeller is a little off, but That makes sense about the oil/gas mix...Should I cut back on the oil/gas mix? I'm using 50/1 -- 3oz. to the gallon. If one does the math, it's 2.6 oz to one gallon. Would the extra oil make a difference? I haven't replaced the seals on the lower unit screws, but will when I replace the lower unit for sure!! Any other tips When I reinstall the lower unit, like extra calking aroung anything? Thanks again,,,,Dan

 

[rickdb1boat]

Re: Black Oil Coming Out By Prop....HELP!!!

50:1 is correct. Don't lean the mixture out anymore than that. 2.65 ounces per gal is correct or 1 pint to 6 Gallons of gas. No caulking nessesary or required. Let us know how it goes and if you have any questions, just ask...

 

[dajohnson53]

Re: Black Oil Coming Out By Prop....HELP!!!

In my experience, the black oil oozing stuff is pretty much a "normal", or at least common part of 2 stroke exhaust. My guess is that the oil in the lower unit oil is a different issue - like someone suggested, the 0 rings on the fill and vent screws possibly.<br /><br />Regardless, don't go with less oil than the 50:1 mix.

 

[Imtrying]

Re: Black Oil Coming Out By Prop....HELP!!!

To all....Before I left for work tonight...I noticed the shift lever housing bolts were loose, and after taking the housing off, I noticed water under the gasket. Again, I rebuilt the lower unit this winter with all new seals, some bearings, shims, impeller, etc. However, I didn't have all the correct bolts to bolt everything down the first time I put the lower unit back together. When I got home from work, I installed the correct bolts to bolt down the shift lever housing, with some gasket sealer too, and will install the lower unit sunday....With that, and installing new lower unit seals on the gearcase screws...I'm hoping that will take care of the "milky" oil in the lower unit....I will run the motor in a tank, and let you all know the outcome.....Thanks again Guys....Dan

 

[Imtrying]

Re: Black Oil Coming Out By Prop....HELP!!!

To all those interested....The Black oil problem was solved by the "experts" on this site...Thanks to all. Now the "milky" oil in the lower unit.....problem solved!! Whet out fishing today, caught a few, but really wanted to test motor again......Drained the oil, and , clean as when I put it in!! What a great site!!!! Thanks Again.....Dan