Transmission Coupler Clearance Problem After 80A Swap

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  • GBoucher
    • Jul 2020
    • 16

    • Nashville, TN

    • 1997 Ski Nautique

    Transmission Coupler Clearance Problem After 80A Swap

    I have just swapped out the old PCM 40A transmission for a new 80A in my 1997 Ski Nautique. After installing the transmission, I have now run into an issue while trying to do a shaft alignment.

    The shaft extends beyond the mating surface of the coupler, and butts up against the nut on the back of the transmission; this does not allow the coupler to actually contact the transmission's side of the coupler. On the old 40A, the transmission nut was set deeper, which meant there were not any clearance issues.

    Is my shaft coupler incorrectly installed too far onto the shaft? Should I remove the coupler and reinstall so that the shaft does not protrude past the mating surface? If so, is it OK to attach the coupler bolts and just tighten them until the coupler pops off, using the shaft itself as the spacer? Is there any reason that I need to replace the coupler itself?

    Here is the shaft sticking out past the coupler:
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    Click image for larger version

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    This is as close as the couplers can get currently:
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    Here is the old 40A transmission, you can see how much more clearance there is with the nut:
    Click image for larger version

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    Click image for larger version

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  • jpwhit
    Senior Member of PLANETNAUTIQUE
    • Aug 2016
    • 517

    • Cary, NC

    • 1998 Ski Nautique 2012 Nautique 200 2014 MasterCraft X25 . 2019 MasterCraft ProStar

    #2
    Yes, you need to reposition the coupler on the shaft to get the right clearance for it to work with the 80A. I doubt the coupler was originally installed like that, I suspect it slide in coupler over the life of the boat.

    Comment

    • GBoucher
      • Jul 2020
      • 16

      • Nashville, TN

      • 1997 Ski Nautique

      #3
      Ok got it, thanks for the response. I didn't think it would have been possible for the coupling to just slide further back than it was supposed to, I figured it would have been limited by the keyway. I'll try to pull it off and reposition. Is there a recommended distance from the end of the shaft it needs to be?

      Comment

      • charlesml3
        1,000 Post Club Member
        • Jan 2008
        • 2453

        • Lake Gaston, NC

        • 2022 G23

        #4
        No, but keep in mind that this is going to push the prop back a bit. Probably not enough to matter, but keep an eye on that as well.

        -Charles

        Comment

        • 625262
          • Oct 2024
          • 3

          • Saint Charles, MO

          • Bluewater 51' 1984

          #5
          Captains
          I am interested in buying a couple of PCM 40A / Ratio: 1.23 cores......
          Capt Alan Deutschmann, Pres.
          Midwest Marine Services
          cell: 314.581.0514

          Comment

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