1957 Johnson 35 hp Mercury switch

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  • January 13, 2018 at 4:05 pm #8997
    RICHARD A. WHITE
    Participant

      Lifetime Member

      Working on this for a club member, While giving it a final once over, I noticed the wiring for the Mercury switch had major cracked and missing insulation. I have a NOS Mercury switch, but the wiring for the 2 are not the same, mine has a knife switch, his has an eyelet at the end of a longer wire.
      I can’t think of any reason why mine won’t work if I splice the proper length wire and ring to it.

      Thoughts?

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

      January 13, 2018 at 4:08 pm #69616
      wbeaton
      Participant

        Canada Member - 2 Years

        Not that I can think of. As long as the mount is the same it should be fine. Its just a mercury switch.

        Wayne
        Upper Canada Chapter

        uccaomci.com

        January 13, 2018 at 4:58 pm #69618
        chris-p
        Participant

          They are for different motors, but as Wayne states, you can modify it to suit.

          Your switch with the knife connector is for the earlier models, the 25/30hp versions. They did not have an inline vacuum cut out like the 35hp you are working on wired to the mercury switch. The lead from the mercury switch simply had a knife connector, which attached to the lead coming from the push button starter switch, to supply the ground for the push button starter to activate. Prevented started at high throttle settings.

          As you can see on his 35hp, they added an inline cut out switch, so the lead has an eyelet to connect to the post on the cut out switch. Different set up, same principles.

          January 13, 2018 at 8:02 pm #69626
          RICHARD A. WHITE
          Participant

            Lifetime Member

            Well now I am completely puzzled as this motor as it arrived to me HAS a cutout switch, And the wire runing to the points……..

            LOL Go figure

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

            January 13, 2018 at 8:04 pm #69627
            chris-p
            Participant

              Yeah that is correct. It should, and would have the mercury switch with the eyelet.

              The earlier version, the 25/30hp didn’t have the inline cutout switch, so had a mercury switch with the knife disconnect to attach to the wiring harness.

              January 13, 2018 at 8:06 pm #69628
              RICHARD A. WHITE
              Participant

                Lifetime Member

                Sorry I typed that wrong, the 1955 I have in the shop I am restoring HAS a cutout switch and wire in the mag…

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

                January 13, 2018 at 8:12 pm #69629
                chris-p
                Participant

                  Not like this then?

                  Attachments:

                  January 13, 2018 at 8:17 pm #69631
                  RICHARD A. WHITE
                  Participant

                    Lifetime Member

                    Like this….

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

                    January 13, 2018 at 8:19 pm #69632
                    frankr
                    Participant

                      US Member

                      1955 HAS a cutout switch, not connected to the mercury switch. The base of the cutout switch was grounded to complete the circuit, and worked any time the vacuum was too high.

                      35hp also had a cutout switch, but the base was mounted on a plastic plate. The base was grounded through the mercury switch, so it only worked when the vacuum was too high AND the throttle was at a slow setting.

                      Reason: The 35hp had the fuel-saver "Cruise Throttle". There was a possibility of the vacuum switch causing a high speed miss when the throttle was in cruise throttle position. To prevent that from happening, the cut-out switch base was not grounded (was disabled) in cruise throttle position, but was grounded and enabled at slow position.

                      January 13, 2018 at 8:20 pm #69633
                      RICHARD A. WHITE
                      Participant

                        Lifetime Member

                        Whew!, Thanks Frank, and Chris_P..lol

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

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