1978 6 hp Evinrude Crankcase Leak

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  • September 12, 2016 at 12:10 am #5229
    raglover
    Participant

      I have a leak in the lower left crankcase joint on my 6. I pulled it apart, see a small blemish on the halves and I’ll polish an reseal.

      A question that has been asked a million times and I am still a little confused, what sealer?

      I use 3m 847 for everything, at least everything with a spaghetti seal, omc lower units and crank cases. This model has no spaghetti seal. Is this where I use a different type? I have read on anaerobic types that require a primer and such, but also see people using 347.

      What type would be best?

      Sorry for a dead horse question, thanks for the help

      September 12, 2016 at 12:19 am #43852
      fleetwin
      Participant

        US Member

        The answer is either type of sealer will work fine. The 847 is much easier to use and much more forgiving though. The anaerobic sealers require careful prep, and will not work well without it…
        I would check those crankcase halves very carefully before reassembly, you sure don’t want to get this thing together only to see it leak again…
        Once you have the halves cleaned and prepped, you might try assembling it "dry". Then go around the halves with a feeler gage to ensure the halves are fitting together properly…

        September 12, 2016 at 12:46 am #43855
        raglover
        Participant

          Thank you! I will check the halves well.

          September 12, 2016 at 4:21 am #43866
          amuller
          Participant

            Check it on a lapping plate?

            September 12, 2016 at 1:16 pm #43878
            frankr
            Participant
              quote amuller:

              Check it on a lapping plate?

              Be very careful with any lapping you may attempt. A thousandth taken off the surface is a thousandth taken off the bearing fit. However, I suspect amuller is suggesting a lapping plate and some blue to check flatness.

              September 12, 2016 at 4:05 pm #43886
              amuller
              Participant

                Well, of course you don’t want to take off enough material to ovalize the bearings. If it were mine I’d probably check the halves against each other, with feeler gauges, and also individually against a flat surface. Could be there is a segment of the faying surface wanting to be built up. I imagine you don’t want to dismantle the thing so far a large number of times…..

                September 12, 2016 at 6:25 pm #43900
                Mumbles
                Participant

                  The Permatex 51531 Anaerobic Flange Sealant or Gasket Maker will fill gaps up to 0.015" and doesn’t require using the primer unless you are going to be running the motor the same day you apply the sealer. The surfaces must be clean and free of all the old sealer and any oil or grease. Brake cleaner or lacquer thinner will degrease the surfaces. This stuff is pretty much the same as OMC Gel-Seal and if allowed to set up overnight, will work fine.

                  https://www.amazon.com/Permatex-51531-A … B000HBGL6O

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