Re: johnson lt-10

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  • lakeofwoods


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    #6740

    As you can see it sparks across the top with the spark tester. It does eventually spark in the window as well though.


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    lakeofwoods


    Replies: 25
    Topics: 3
    #56079

    The tester


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    garry-in-michigan

    Lifetime Member
    Replies: 3583
    Topics: 31
    #56086

    That looks normal to me. It indicates the resistance across the gap in less than the resistance of the tester. The voltage being developed should be enough to fire the plugs. If one plug does not fire, it is a short or open circuit in one of the external high voltage wires or hardware. . . 😉


    lakeofwoods


    Replies: 25
    Topics: 3
    #56094

    Okay so if I pick up some plug wire and caps it should jump the plug before that gap ?


    lakeofwoods


    Replies: 25
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    #56095

    any idea looking at the picture which side fires top plug ? the wires were cut off when I got it .


    garry-in-michigan

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    #56100

    Turn the flywheel so one piston is at top dead center. Measure the resistance of the spark plug wires. The one with the highest resistance is the one that goes to that cylinder. One spark plug wire measures the coil resistance, the other is shorted by the distributer brush and does not. . . 😆


    Buccaneer

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 7493
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    #56107

    Good tip Garry. I was just wondering the same thing on the HD-15 Johnson I was
    working on today. I eyed up the grounding contact in the flywheel as I put
    the flywheel on, with the top cylinder at TDC, then decided which end of the coil
    should be "top". Funny, but later on I found my diagram where I noted which
    side of the coil was "top" (according to the plug wire band) and it
    was opposite of what I guesstimated. I’ll try your Ohm meter method
    tomorrow!

    Prepare to be boarded!


    lakeofwoods


    Replies: 25
    Topics: 3
    #56112

    I will have to put some new plug wires on it with caps and see if it has spark at the plugs . With the spark tester it sparks up at the coil as seen in the picture but with my meter it shows a open on both sides of the coil on the secondary coils.


    garry-in-michigan

    Lifetime Member
    Replies: 3583
    Topics: 31
    #56127

    It would show open to ground from either end of the coil unless the other end was grounded. . . 😀


    Buccaneer

    US Member - 1 Year (includes $3 online payment fee)
    Replies: 7493
    Topics: 1072
    #56132

    Garry, regarding your "tip" below. I tried it this morning,
    and it worked like a charm! Thanks.

    quote Garry in Tampa:

    Turn the flywheel so one piston is at top dead center. Measure the resistance of the spark plug wires. The one with the highest resistance is the one that goes to that cylinder. One spark plug wire measures the coil resistance, the other is shorted by the distributer brush and does not. . . 😆

    Prepare to be boarded!

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