Johnson Seahorse TD20

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    DavidH


    Replies: 2
    Topics: 1
    #217563

    I have been restoring a 1948 Johnson Seahorse TD 20 5 HP outboard. I now have it running well but it will not shut off.
    I have located the Stop switch contact under one of the coils. There was some corrosion I have cleaned up but there were also two eyelets attached that appeared to have wires broken off. If these wires are required, where should they be connected to?
    Your help is much appreciated.

    Thanks, David

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    aquasonic

    US Member - 2 Years
    Replies: 411
    Topics: 32
    #217579

    David, those coils have an extra ground wire that is part of the “kill switch” setup on that motor. When the throttle lever is moved to stop, the lever contacts both coil ground wires that sit in a tiny housing built into the magplate. The wires and eyelets are alternated with insulating bakelite washers within the housing so they don’t contact each other. It sounds as though the kill switch wires may be broken off.

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    DavidH


    Replies: 2
    Topics: 1
    #217603

    The kill switch wires were completely missing. To match the original wiring layout, can you tell me where the kill switch wires should be connected? The three ground wires look to be orange (to the magneto plate), green (to the points breaker), and black (to the magneto laminated pickup)

    Thanks!

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    aquasonic

    US Member - 2 Years
    Replies: 411
    Topics: 32
    #217637

    It’s been a long time since I have worked on a TD-20, so I went and took a good look at an extra magplate on hand. Looking at the back of the coil, there is a short, 2-3″ black wire that goes to your left and straight to ground with a hex nut connection. To your right are two wires, mine are green. The longer wire goes underneath the lamination to the points, the shorter wire goes above attaches to the top of the coil lamination on your right side.

    Each set of points has two wire connections. The connection closest to the coil is where the longer coil wire and the condenser attach. The further connection is where the kill switch wire connects. So the kill switch wire is independent, and connects the points to the top side of the insulated post/housing. Both kill switch wires go to the same point so they are two different lengths.

    The connectors at the insulated post/housing are alternated with insulating bakelite washers, and because of the insulating washers does not ground under running conditions. The only metal touching the wires is the screw/post. The kill switch comes into play when the magneto advance lever gets moved all the way to the operators left, and contacts the bell shaped housing on the bottom of the magplate, The bell shaped housing contacts the screw/post, and shorts out the points, shutting down the ignition.

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    DavidH


    Replies: 2
    Topics: 1
    #217654

    Thanks! Just what I needed. You saved me hours of head scratching and frustration.

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