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How to check for bad coil pack?

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  • How to check for bad coil pack?

    Is there a way to tell if you have a bad coil pack without a spark tester. I have not invested in a timing light or spark tester yet. My engine is a starlight 85 hp evinrude mid 70s model. It ran fine all summer. The last time I took the boat out it would start up but stall everytime it was shifted into gear. I have rebuilt the carbs thinking this was the problem but i am still having the same problem. The engine will run with the muffs on and stay running in gear. If the lower unit is submerged however it will stall every time shift into gear. I have also done a compression and leak down test and everthing checks out fine. I believe the problem is ignition related since this issue started "all of the sudden". I would apreciate any advice you all can offer.

  • #2
    Re: How to check for bad coil pack?

    Start with the spark test. Take out all of the plugs and rig a tester with a 7/16 gap. You can use a dry board and nails if you want, just make sure the gap is wide - at least 3/8. You want to see a sharp blue spark.

    Disconnect the black and yellow kill wire at the powerpack so that you can rule out ignition switch and kill wire.

    The V4 engines have to have absolutely clean connections on the coils and grounding strap. So get your tools and take the wires off and clean everything, including the mounting bolts for the ignition coils. Check the spark plug wires carefully, and make sure that they are not automobile wires. If the spark plugs have been hit or dropped, the ceramic may be cracked and they will not work.


    • #3
      Re: How to check for bad coil pack?

      Joes technique for coil testing. Although I would test the spark as Ezeke stated, then swap the known good coils with suspect ones if need be.

      (Magneto Capacitance Discharge Coils - Continuity Test))
      (J. Reeves)
      Check the continuity of the ignition coils. Remove the primary orange wire from whatever it's connected to. It may be connected to a powerpack screw type terminal, a rubber plug connector, or it may simply plug onto a small boss terminal of the coil itself.

      Connect the black lead of a ohm meter to the spark plug boot terminal, then with the red ohm meter lead, touch the ground of the coil or the powerhead itself if the coil is still installed.

      Then touch (still with the red lead) the orange wire if it's attached to the coil, or if it's not attached, touch the primary stud of the coil. You should get a reading on both touches (contacts). If not, check the spring terminal inside the rubber boots of the spark plug wire. Poor or no continuity of a coil is one reason for s/plug fouling.

      However, if it dies when put in gear,it does sound fuel delivery related, not ignition. Where the carbs thoroughally cleaned? Check to see if the timer base (starboard side, under the edge of the flywheel, linked to the throttle lever) moves smoothly without sticking when you advance the throttle.

      Take the airbox cover off & observe whether the throttle plates are parallel.

      Also, the timer base should start it's travel before the throttle plates start to open, or else she will fall flat when you give her the throttle.

      Johnson - Evinrude Top Secret Files:

      Proudly Dedicating My Time To Antique And Vintage Style Outboards!


      • #4
        Re: How to check for bad coil pack?

        When you cleaned the carbs, did you remove the jet's to make sure they were clear? Sound like a fuel delivery problem.


        • #5
          Re: How to check for bad coil pack?

          Yes I did. I have noticed that the timer base is not starting to travel before the throttle plates open. Sometimes it does not eevn touch the spark advence screw at full throttle. Also the timer base is not moving backwards to its starting position when you put the throttle back in nuetral. I believe there is something wrong with the whole throttle and spark advance arm. Does anyone have some video or pics of how this arm should travel?


          • #6
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            Re: How to check for bad coil pack?

            Check to see if the stator has melted and the epoxy run down on the timer base. I have seen this stop the entire base from moving. It may also need a little grease under the base. This is about the only thing I can think of.
            25 Hydra Sport
            300 V8 Johnson.