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Thread: Outboard Spark question.

  1. #1
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    Default Outboard Spark question.


    Just recently purchased a 2001 Johnson outboard and last weekend while on the water I was having some issues thinking that it was misfire. Came home and once it got dark I'm pulled plug wires off one of the time while engine was running and could see faint Sparks coming from the boots on the coil the ground. Thinking that it was wore out plug wires I replaced them along with the coils and new plugs. But as luck would have it I was testing my install and it's doing the same thing when I disconnect a plug wire I'm seeing the same Sparks. Is this a normal thing? It's also kind of hard to determine if the spark is coming from the top of the plug wire where it attaches to the coil or if it's the trigger wires coming from the power pack

    Sent from my SM-S215DL using Tapatalk

  2. #2
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    If the plug wire is disconnected while the motor is running, that voltage has to go somewhere, and will find the path of least resistance, sometimes around the boot near the coil to the mounting bolts. That is normal.

    If the plug wire is hooked to a grounded spark plug and you are still seeing sparks, you have a bad coil or wire, that is not normal.

  3. #3
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    A little aside from your problem, I don't like to pull plug wires off an engine with the motor running. If you are out somewhere and no other option it's OK I guess, but I like another option like putting a timing light (Clip on) on each wire one at a time and checking for a good bright quality flash with each one looking similar. I like a light dab of dielectric grease in the plug wire caps on the rubber as well as the metal (I use a tooth pick), as It conditions the rubber and helps them ease off the plug later on. I make sure the metal ends are tight on the plugs, a little dielectric grease there, and anti seize on the base threads. I carefully get them started, and always torque them. Aluminum is just not very forgiving.
    Remove the cowl sometime after dark and crank it up and look for exposed current on the wires. There should be NONE. There's the normal. As rare as they get replaced, I only run premium plug wires and keep them isolated from each other.
    After many years of working on Small Block Chevys, both stock and heavily modified, those basics have always served me well.

  4. #4
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    Check the ground on the coils also. And as said check that the metal connector in small boots from cdi box are tight. Sometimes if small boots (orange)
    Don't snap on , they will slide off. I have to sometimes cut about 1/16 off boot end to get them to stay on.

  5. #5
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    I ended up removing the coils and noticed they were both cracked so I replaced them both with Sierra brand. As my luck would be, one them had no fire to the plug. Replaced the coil with of the old ones and I had spark. So I returned both and for now waiting on OEM coils. I also went ahead and ordered a new power pack and optical sensor as well. I read that part of what I am experiencing can actually be slow kicking in and not actually a misfire.

    Sent from my SM-S215DL using Tapatalk

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