Martin 75 Synco Twist Plug Wires Binding

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  • January 17, 2017 at 10:43 pm #6129
    Buccaneer
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      US Member

      I put new coils on this Martin last year. It ran but had some issues, so I just put
      new crankcase seals and poppet valve o-rings in it, etc.
      I wasn’t happy with the spark plug wire routing last year,
      and even less happy this year when trying to put it back together.
      The magneto is advanced and retarded via cables on each side
      of the power head that also attach to the twist grip.
      The spark plug wires bind up when the magneto is moved, as the wires
      have to drag over a cable pulley on one side, and a cable bracket
      on the other side. I can get it to work so-so with the gas tank off,
      but the plug wires have even more to bind on with the tank on.
      Even though the old wico coils were replaced with OMC, the plug wires
      still exit the mag plate thru the original locations, so that should not
      be an issue. The original plug wires were chaffed from rubbing on
      said points, so I’m beginning to think it’s a design issue.
      (They later came out with the "Twist Shift" model, so perhaps this
      issue went away?)
      One page in the manual shows the plug wire routing, but that hasn’t
      cured the problem.
      Anyway, has anyone had the same problem with this model, and if
      so, did you find a cure?
      Thanks!

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      January 18, 2017 at 1:09 am #51227
      jerry-ahrens
      Participant

        US Member

        You might consider getting in contact with Russ Larson for an answer to your problem. It doesn’t look like there are any other options, as far as re routing the wires. One thing I’ve noticed about the modern copper core plug wire, is that the insulation isn’t near as abrasion resistant as the original stuff from the 50’s. Lately, I’ve been reusing most of the original plug wires on the motors I work on, just because it has/will hold up better. I’d love to have a big roll of the 50’s spark plug wire, just to have when I need it.

        January 18, 2017 at 2:14 am #51237
        Buccaneer
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          US Member

          Jerry, thanks for your response. I purchased the seals, etc., from Russ,
          so I guess it wouldn’t hurt to see if I can direct him to this thread.
          Thanks!

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          January 18, 2017 at 11:18 pm #51290
          Buccaneer
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            US Member

            Jerry, Russ concurred with you regarding the modern spark plug wire not being
            as abrasion resistant as in the past. Also he suggested shielding the plug
            wire with aluminum.
            I didn’t do that, but messed around for an hour with wire routing and "hold downs"
            before I was satisfied.
            I added a hold-down to each plug wire on the front of the power head, forcing
            the plug wire to make a "loop" that more or less goes over the cable pulley
            on one side, and cable bracket on the other.
            I remember on my 1948 Evinrude Sportwin 3.3 hp project that the original plug
            wire had some special routing, and it was a lot more "limber" than modern
            wire. Installing modern plug wire on this unit didn’t work out well.
            Anyone selling "limber" plug wire?
            Anyway, the Martin is all back together…… just have to wait until April
            or so until I can fill up the test barrel to try it out again 🙁

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