Weak to no spark

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  • July 16, 2017 at 12:11 am #7652
    Goman
    Participant

      This is a Johnson K45 that I’m working on. I can pull it over a few times and get a spark around an 1/8th of an inch then after that I don’t get no spark at all. I rebuilt the coil with two of the OMC coils. At the spark plug wire leads I’m getting a reading of 15 with the meter set at 1k ohms. I’m weak on the electrical stuff. I’ve used two different new condensers one at 26 the other at 32uf. The magnets seem strong enough compared to a couple of others I’ve worked on. The coil heels are not rubbing. The only difference I see from a Lockwood I have worked on is that I run the green wires from the coils directly to the points. Could that be my problem? I may have wire arcing somewhere but I’m not seeing it. As always thanks for the help.
      Glen

      July 16, 2017 at 3:02 am #61677
      Mumbles
      Participant

        If the magnets are strong, I’m guessing the capacitance is wrong. The OMC coils are meant to be matched up to a condenser with a rating of .20-.22 uF +/-. If the coils are hooked up in parallel, I’m thinking they would need a capacitance of .40-.44 uF. Capacitors with a .22 uF rating can be doubled up in parallel to get the .44 uF rating. The OMC/BRP 580321 condensers are matched to these coils but you can also use Vishay axial caps from Digi-Key.

        https://www.digikey.com/products/en?ven … =bc2609-nd

        July 16, 2017 at 1:54 pm #61692
        Goman
        Participant

          Thanks Mumbles I’m going to go ahead and order that. My magnets will hold a regular size crescent wrench upside down until I give it a little shake then they fall off..best way I can explain that. I used the 18-5199 Sierra condenser from Napa it’s supposed to be the same. It was the one that measured 32uF. Maybe the heat messed it up when I cut the tab off 😳 It still seems I should get spark every time I pull it over? If the Vishay part doesn’t work I guess I’ll take it down and look for a nick in a wire or bad connection somewhere.

          July 16, 2017 at 6:03 pm #61706
          The Boat House
          Participant

            This may be a stretch but while you’re waiting
            for your condenser to come trying pulling it over
            a few times and then take a wire and ground
            the coils and the condenser at the points to the
            magneto plate.

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