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1979 Evinrude 115, milky oil in lower unit

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  • 1979 Evinrude 115, milky oil in lower unit

    Hello all, I have another situation.
    Earlier in the week when I trimmed my outboard all the way up, I noticed gear oil running down the back bottom edge of the lower unit. Just enough to make a 6 or 8 inch stain in my driveway, but definitely gear oil. Now today, I drain the lower unit and get a little stream of clear water followed by some milky and some amber gear oil. I have the water pump kit, that's why I was draining. Since I had oil out the top edge of the lower unit, I'm thinking the water pump seal might be my culprit of the water in the lower unit and I might fix it when I rebuild the water pump. But if I rebuild the water pump and then have to go back in later to do other seals, it's like doing it twice. Any suggestions?

  • #2
    If seals are original you need a complete seal kit.----Do them all.


    • #3
      Have it pressure and vacuum checked before you tear it down. That way there's no guessing as to where it's leaking.


      • #4
        I agree with racerone. If you are going to pull the lower unit, you might as well replace all the oil seals. I had the same issue with my boat about a month ago. I saw gear lube seeping from the gap between the upper and lower unit. I found that I had only 1 prop seal, instead of two, and in my opinion, I believe that was where the leak originated. In addition to replacing the prop seals, I figured I should go ahead and replace the water pump seals and the shift shaft seals (o-rings) as well. Peace of mind if anything...and if you're as lucky as me, when you decide not to replace the other seals, something will happen to the other seals and you'll be pulling the lower unit yet again! Couple of reminders...be sure not to damage/nick/scrape your prop shaft when pulling the seals (unless you plan to remove your bearing carrier, which can be a real pain in the @$$). There are some great vids on YouTube which provide some creative ways to remove oil seals without pulling the bearing carrier. Lastly, I would lightly sand my drive shaft and prop shaft with 200+ grit sand paper if it is rough and then lightly grease it. Good luck.


        • #5
          sounds like some metaphysics or theology going on there, BigSur . I would buy the seal kit, but at least pressure test it first if doing the job(s) myself. Pressure testing is kind of fun, and can vacuum test yourself as well (recommend a MityVac). But pressure testing first will tell you how to identify a leak -- should follow up after any seal work with another test to check results (will need to know what to look for).


          • #6
            Thanks for the sound advice gents. I did see a YouTube video on pulling the bearing carrier. I have a decent tool set at home, but only a 2/3 jaw puller, not the one he had to use. Anyone know the seal kit part number for a 115999R evinrude? the gearcase exploded view on here doesn't show a seal kit, only the impeller and pump kits.


            • #7
              Looks like maybe this one?

              ​Seems like it's for a 79 115, but check it out to be sure it's a fit for you.. LOL


              • #8
                Well, the description of pulling the bearing carrier was an understatement.... What a booger. Now after putting all new seals in, the bearing carrier o-ring is leaking. I put the gasket dressing on it as instructed in the manual. I got up to 8 psi and is started weeping by that o-ring. The groove for that o-ring was about wide enough to put 2 of the provided o-rings in it. If I have to pull that SOB again, I'm getting a thicker o-ring from somewhere else. Maybe I should have waited more than 5 minutes from install to pressure test to let the gasket sealant set up more. Maybe I didn't get all the crud from the spot where the o-ring makes it's seal. Someone LIE to me and tell me to wait until tomorrow, test again, and the gasket dressing will seal it up!!! LOL


                • #9


                  • #10
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                    Hello everyone .. I have a 1977 Mercury 850EL 85 hp,...I hooked up muffs to run in drive way and noticed water leaking from the lower unit at the seam where it meets the upper unit ... is this catastrophic .. or do all I need is a seal kit?