1956 Johnson 15HP Rod bearing clearance

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  • This topic has 25 replies, 6 voices, and was last updated 3 years ago by bobw.
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  • January 3, 2022 at 1:33 pm #252269
    frankr
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      Look inside the pistons. One side should be marked “LOOSE” or “L”. That side is a slip fit, while the other side is a press fit. If you intend to save or re-use the piston, you must drive the pin from the loose side (through the tight side (which you hopefully have supported). Driving it the wrong direction will distort the piston. Of course that doesn’t matter if you intend to scrap it anyway.

      January 3, 2022 at 2:01 pm #252270
      olcah
      Participant

        US Member

        Found the ” L ” . Thank you.

        January 3, 2022 at 4:31 pm #252275
        Mumbles
        Participant

          Just a heads up but the original part number for the rings, 301787, superceded to 486278 which superceded again to the current 378416 part number. These rings are the same as ones used in the ten horse motors thru ’63. The rest of the P/N’s appear to be current.

          The bore and stroke of the FD-10 is 2 3/8 X 2 1/4 while the FD-11 and later are 2 1/2 X 2 1/4. The cranks have the same stroke but I believe the FD-10 crank might be slightly shorter in length, hence the different part numbers for them.

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          olcah
          January 3, 2022 at 7:19 pm #252296
          bobw
          Participant

            US Member

            You can make a simple piston support cradle with a block of wood and the appropriate size hole saw. As Frank noted, you need to support the piston when removing or installing the wrist pin.

            01-Piston-Cradle

            Bob

            1937 Champion D2C Deluxe Lite Twin
            1954 Johnson CD-11
            1955 Johnson QD-16
            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."

            January 3, 2022 at 8:01 pm #252307
            olcah
            Participant

              US Member

              Bobw,

              I assume there is a hole in the center of the cradle to allow the pin to drop out of the piston when the pin is driven out.

              Thank you.

              January 3, 2022 at 10:11 pm #252312
              bobw
              Participant

                US Member

                Yes, there is a pin hole (pardon the pun).

                Bob

                1937 Champion D2C Deluxe Lite Twin
                1954 Johnson CD-11
                1955 Johnson QD-16
                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."

                1 user thanked author for this post.
                olcah
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