FD-15 lower unit

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  • rjoynt

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 140
    Topics: 26
    #4432

    Changing the seal on the driveshaft. There were two seals. First one was in normal, the top one put in upside down. The kit calls for one seal and the part list calls for one. Any reason why there were two? There is room for both. Baffled and confused. 1961 18 hp Johnson.


    fleetwin

    US Member - 2 Years
    Replies: 4737
    Topics: 46
    #37683

    Well someone was probably just trying to use a dual seal set up like found on later model engines. The outer seal’s lip faces out, meant to keep water from being pulled inside the gearcase. The inner/lower seal’s lip faces down to keep gear lube from leaking out.


    rjoynt

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 140
    Topics: 26
    #37684

    Sounds reasonable. But the driveshaft now has a groove where the seal lip is. The lower unit passes the air pressure test of five pounds for 15 minutes but still seems to get water in it. I’m thinking that the next thing is to replace the driveshaft. Thoughts?


    chas56x

    US Member - 2 Years
    Replies: 49
    Topics: 6
    #37685

    I am thinking speedy sleeve to cover the groove worn in the drive shaft.


    rjoynt

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 140
    Topics: 26
    #37686

    Not familiar with that. What is it?


    frankr

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 6715
    Topics: 51
    #37687

    Speedy Sleeve is a thin stainless steel sleeve that goes over the worn area. They aren’t cheap. Neither is a drive shaft. How about the shift rod seal? And of course there are other places too, like the spagetti seal, etc, etc. How bad is it leaking anyway? You might consider a few extra oil changes if we are talking drops.


    rjoynt

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 140
    Topics: 26
    #37688

    Frank, thanks for the response. The other seals are good. Under pressure, the driveshaft seal did leak originally. I pulled the two seals that someone had put in. Evidently it must have leaked in the past. Time to figure out how much to put in it.


    jerry-ahrens

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 986
    Topics: 40
    #37690

    Aggreed,If you haven’t already changed it, the shift rod seal [o ring] is most likely the culprit…. very common to leak on most 50’s and 60’s OMC outboards. Easy to change with the correct tools. When you have the lowerunit pressurized, try wiggling the shift shaft around a bit to see if it leaks while shifting in and out of gear.


    beerman57


    Replies: 596
    Topics: 126
    #37692

    Did you shift it, wiggle shift shaft and drive shaft, turn drive shaft while doing the pressure test?


    rjoynt

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 140
    Topics: 26
    #37693

    Yep, did all of the above. Replaced many of them, have a couple dozen o-rings in the parts drawer. OEM rings. I use the Stevens pump for pressure testing. I even have Frank’s special tool! Thanks once again Frank!!

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