1958 FD-12 18 hp drive shaft seal(s)

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  • September 24, 2015 at 11:52 pm #2622
    RICHARD A. WHITE
    Participant

      Lifetime Member

      I recall seeing this question asked before, but ya know I did not own one of these then… I removed one seal from the upper half of the gear case. It was just under the impeller plate, but they sent 2 seals to replace and I do NOT recall how they should orient to be proper. Both openings up? both openings down, top seal opening up and bottom seal opening down?

      Oh boy..LOL

      Thanks

      Richard

      http://www.richardsoutboardtools.com
      classicomctools@gmail.com

      September 25, 2015 at 1:33 am #24560
      beerman57
      Participant

        Where did you order from? Most places just send the one single lip seal. Pretty sure you put the 1st seal in open side down, 2nd seal open side up.

        September 25, 2015 at 10:48 am #24575
        frankr
        Participant

          US MEMBER PAY BY CHECK

          Depends on if there is enough room for two seals. If there is enough room, install the way beerman said. If not enough room for two, install one open side toward the oil.

          September 25, 2015 at 11:51 am #24579
          Mumbles
          Participant

            Sounds like you ordered the Sierra 18-2684 seal kit. Don’t worry. It comes with two seals for both shafts but since your motor only needs one, you end up with an extra one for your next project. Install it with the lip facing in and you will be OK.

            September 25, 2015 at 11:57 am #24580
            wiscoboater
            Participant

              Your going to love that motor Richard. The more FD’s I collect, the more I want. Great running motors, very surprising power to weight ratio, truly one of Johnsons best. Enjoy it!

              September 25, 2015 at 1:52 pm #24587
              beerman57
              Participant

                Can I add a question on this subject? When 2 seals are too thick, will one keep the oil in and water out? Prop shafts are the same way – original seals are thick brass, what I call dual-lip, but 2 single lip seals are usually too thick. Will one do both jobs?

                September 25, 2015 at 3:19 pm #24592
                RICHARD A. WHITE
                Participant

                  Lifetime Member

                  I got this motor for $100, carry handle was broken, well found one of those and decided that this motor will be my, " I don’t want no issues, so the wife won’t complain about a breakdown " motor. Decided that going thru gear case and the impeller was the only way to do it right, ignition as well. It was one butt ugly motor so I tore it down and found the cylinders look great. I am blasting the ugly off and will order the correct paint to make her purdy.

                  I will be begging for a good used tiller grip so if you are reading this and you have one…please contact me…LOL

                  http://www.richardsoutboardtools.com
                  classicomctools@gmail.com

                  September 25, 2015 at 4:39 pm #24596
                  frankr
                  Participant

                    US MEMBER PAY BY CHECK
                    quote beerman57:

                    Can I add a question on this subject? When 2 seals are too thick, will one keep the oil in and water out? Prop shafts are the same way – original seals are thick brass, what I call dual-lip, but 2 single lip seals are usually too thick. Will one do both jobs?

                    Beer, I think you will find the thick CR brass seals were only single lip. So, in theory at least, the new single lip seals would do the same job, assuming the quality is equal. One advantage to the thin seal is you can install it at a different depth and maybe have it ride on an un-worn area of the shaft. Yeah, I still like the old, obsolete CR brass seals. They just seem "right".

                    September 27, 2015 at 11:14 pm #24725
                    sedover
                    Participant

                      As mentioned single seal lips down toward the gearcase. Two seals, back to back, lips down and lips up. The old gearcases were never checked for vacuum just pressure after assembly.

                      With the Sierra kit you have to be careful with the prop shaft seal. If it is still the case, the shielded one supplied has the lips facing out which is incorrect for the solo seal application on the propshaft as the lips need to face towards the gearcase. The correct OEM one is still available for most 18/20/25’s but I’m not sure if all bearing heads will take this seal.

                      As I’m sure you are aware the the real weak link with the OMC gearcases is the shift shaft o-ring.

                      Steve

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