Thread: Bad coil?

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  1. #1
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    Bad coil?

    1985 Johnson GT. Losing some power.When I ran carb cleaner through it,all of the plugs were fouled except one which was clean and dry. When I change plugs around, whatever plug goes there ends up being clean and dry. It did this once before and was a bad coil. How can I further test to see if the coil has gone bad?

  2. Member DoferGofer's Avatar
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    #2

    Re: Bad coil? (Rondojigs)

    <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rondojigs &raquo;</TD></TR><TR><TD CLASS="quote">1985 Johnson GT. Losing some power.When I ran carb cleaner through it,all of the plugs were fouled except one which was clean and dry. When I change plugs around, whatever plug goes there ends up being clean and dry. It did this once before and was a bad coil. How can I further test to see if the coil has gone bad?</TD></TR></TABLE>
    Which plug is clean and dry, and the rest wet and somewhat foul, in your opinion?




    If you can't run with the big dogs, just stay on the porch.

    Model E150DPLIIB, Serial 05311818, Mfg Date 02/2011

    SST... 14 1/2" x 19" 45.0 mph.@4950
    Rebel 15 1/2" x 17" 45.1 mph.@5250
    Rebel 15 1/2" x 16" 44.6 mph.@5300 (Re-pitched/Balanced/Blue Printed by Mark's Props)
    Rebel 15 3/4" x 15" 44.2 mph.@5700-5750

  3. Member
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    #3

    Re: Bad coil? (DoferGofer)

    <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DoferGofer &raquo;</TD></TR><TR><TD CLASS="quote">
    Which plug is clean and dry, and the rest wet and somewhat foul, in your opinion?




    </TD></TR></TABLE>

    middle right side

  4. SC Club Moderator ChampioNman's Avatar
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    #4

    Re: Bad coil? (Rondojigs)

    Move the coil.

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    #5

    Re: Bad coil? (ChampioNman)

    <TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ChampioNman &raquo;</TD></TR><TR><TD CLASS="quote">Move the coil.</TD></TR></TABLE>

    I did. I rotated the middle to the top and top to the middle. The middle plug was fouled and now the top plug wasnot fouled so it points to that particular coil being bad. I also did a compression check and all were the same(98-99).

    tommorrow, Im running another can of Powertune through the system JUST to be sure it isnt just carbon build up.That should also foul the plugs more so I can be sure that the coil in question is bad.

    Any other way to test the coil or does it sound like Im on the right track?

  6. Member DoferGofer's Avatar
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    #6

    Re: Bad coil? (Rondojigs)

    If it was my engine, I would do a compression and leak down test. I suspect the possibility of a blown/leaky head gasket.

    If you can't run with the big dogs, just stay on the porch.

    Model E150DPLIIB, Serial 05311818, Mfg Date 02/2011

    SST... 14 1/2" x 19" 45.0 mph.@4950
    Rebel 15 1/2" x 17" 45.1 mph.@5250
    Rebel 15 1/2" x 16" 44.6 mph.@5300 (Re-pitched/Balanced/Blue Printed by Mark's Props)
    Rebel 15 3/4" x 15" 44.2 mph.@5700-5750

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