vibration and noise in gearcase

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  • March 1, 2024 at 5:08 pm #285438
    bfitz241
    Participant

      US Member

      I sealed up the gearcase on my FD 19 Johnson (https://www.aomci.org/forums/topic/sealant/)  and it worked out really well.

      However, after I filled the lower up I spun it with my makita and it made hell’s own noise.  I mean bad loud.  That and A LOT of vibration.  I know I’m not the first guy in there, but is there any way to tell what gears are in there by measuring or by tooth count?   I didn’t see any part numbers on the gears.

      It sounds like the pinion isn’t meshing properly with the other gears and the lower has a spot in its rotation where it will bind.  You can twist through it by hand, but I know that isn’t right.

      I took it apart again and nothing jumped out at me so if you could tell me what to look for I’d appreciate that.

       

      Thanks

      BF

      March 1, 2024 at 6:45 pm #285444
      frankr
      Participant

        US Member

        My guess is that you are pushing the shaft downward as you are spinning it with that drill.  That is jamming the gear teeth together.  In normal use, the shaft will float upward as the thrust of the gear teeth push them apart.  Easy fix, simply allow the shaft to rise as you turn it.  You aren’t the first guy to discover this, and you won’t be the last.

        March 1, 2024 at 11:59 pm #285447
        bobw
        Participant

          US Member

          As Frank noted, I found this same issue the first time I did a gearcase reseal job when I was putting downward pressure on the driveshaft.  Trying doing a quick reassembly of your gearcase without any sealant, then turn the driveshaft by hand.  If you push down on the driveshaft as you turn it you’ll hear a lot of noise.  Lift up slightly on the driveshaft as you turn it and you’ll see the noise goes away.   Perhaps another thing to check while you’ve got it apart is a missing thrust washer on one of the drive gears which would prevent proper meshing of the gear set.   The original gear set on the FD-19 should have 21 teeth on the forward and reverse gears.

          Bob

          1937 Champion D2C Deluxe Lite Twin
          1954 Johnson CD-11
          1957 Evinrude Fastwin 18
          1958 Johnson QD-19
          1958 Johnson FD-12
          1959 Johnson QD-20

          “Every 20 minute job is only a broken bolt away from a 3-day project.”
          "Every time you remove a broken or seized bolt an angel gets his wings."

          March 2, 2024 at 12:41 am #285448
          jeff-register
          Participant

            US Member - 2 Years

            If I may say also did you put an O-ring below the splines to hold grease on the splines? Please grease only the splines & not the top of the driveshaft as that will cause the driveshaft to not be able to rise for the gearset. Driveshafts have been known to rust to the crankshaft so grease the splines lightly please. Every time it’s removed.

            March 19, 2024 at 10:47 am #286038
            bfitz241
            Participant

              US Member

              update on this:

              Took your advice and made sure I wasn’t putting any pressure on the shaft, and yes the noise went away.  However, even with just the weight of the shaft on the pinion this thing sounds horrible.  The driveshaft would have to be suspended during operation , is that how this works?  I compared it to other gearcases I have and they’re silent compared to this thing.

              This lower had seawater in it and I think the gears aren’t as smooth or flat as they should be .  I’ve got another gearset I’m going to try.

               

              Thanks for the help

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