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how to wire mercruiser shift interupt switch ?

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  • how to wire mercruiser shift interupt switch ?

    i replaced my thunderbolt iv ignition system with an aftermarket mallory marine ylm624 av electronic breakerless distibutor. now i need to figure out how to wire the shift interupt switch. can anyone help? or has anyone ahd to do this before? my new distributor has a green wire which goes to coil positive. red wire coil negative. and brown wire engine ground. the shift interupt switch ground is still hooked up but now the white with green tracer is un hooked. in the stock application it hooks up to the thunderbolt iv ignition module and tee's into the the white with green tracer out of stock distributor. no longer used. any help will be appreciated. thanks all.

  • #2
    Re: how to wire mercruiser shift interupt switch ?

    If you're sure you have the type of interrupt switch that grounds one side, you should be able to run a wire from the coil pos(+) to the interrupt switch terminal block white wire.


    • #3
      Re: how to wire mercruiser shift interupt switch ?

      thanks a bunch ya i was gunna try that. its a 93 it only had one wire going from the switch to the distributor and tees to the ignition module. the other is a black wire assumed to be a ground by me. thanks.


      • #4
        Re: how to wire mercruiser shift interupt switch ?

        If it has a coil --- the distributor makes and breaks that circuit --- by grounding the coil ---- that is the dwell, how long the coil is grounded saturating the coil winding building up a magnetic field --- then the circuit opens --- the magnetic field collapses --- induces a magnetic field in the high tension windings and firing the plug.

        The interrupt switch grounds the circuit when the shifter is moved to kill the engine --- so the normally open switch should work on your application --- connect it to the negative side of the coil --- grounding the circuit and killing the engine during the shift.

        Good Luck


        "If the boat is not sinking or on fire ---- Relax."


        • #5
          Sign up today
          Re: how to wire mercruiser shift interupt switch ?

          I closed your other 2 posts on the same subject. You can bump the post to the top if no one answers after you first post it, but don't repost the same question more than once.
          Don S.

          Please, no PM's (Private Messages) regarding boat/engine problems.
          That is what the forums are for.
          Only forum/moderator issues will be answered in PM's.