coils

Discussion in 'The Projects Forum' started by doodle-bug, May 14, 2008.

  1. doodle-bug

    Thread Starter New Member

    May 14, 2008
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    hello i`m a first timer at this so here goes. i have a onan 4kw generator that hasn`t run in a couple years. i am getting no spark to the plugs the caps test ok but i don`t know about the coil the gen. is a twin cyl onan eng. how can i test the coil or if any one has had the same problem how did you correct it. the coil has to spark plug towers. thank in advance
     
  2. gerty

    AAC Fanatic!

    Aug 30, 2007
    1,153
    304
    Have you checked the oil? Alot of generators have a switch that shuts off the ignition when oil pressure is low. Have rats or dirt dobbers got into it,chewed wiring or nests around pickup? Let us know everything you've checked
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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  4. doodle-bug

    Thread Starter New Member

    May 14, 2008
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    i have checked the oil and its up where its supose to be and in the generator it is inclosed. i have looked all over the unit have found no nests of any kind whatsoever. i was told to remove the strap on the generator to see the comator brushes to make shure that they were not stuck the were not. the generator acts as the starter in the cranking mode. i have checked the points, cond, cap, relays, and wireing. but can not get to fire the plugs. i`ve to get the coil tested to see if it bad no one knows how to test one, a new coil for this is around ninty dollars. i hate to have to buy one and find out mine was good. thank you
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    OK.
    1) Check to see if you are getting power to the + side of the coil.
    2) Check to see what the resistance is from the - side of the coil to the points.
    3) With the points open and power on, you should read about the same voltage on either side of the coil. If not, the capacitor or the point lead wire is shorted, or the coil is open.
    4) Disconnect either the + or - coil lead (whichever is easiest) and measure the resistance through the coil. It should measure at least a few Ohms, but not be either open nor shorted; it's a coil of wire.
    5) Pull off your spark plug wires and measure their end-to-end resistance with your Ohmmeter. If the wires have copper conductors, they should measure nearly 0 Ohms. If they are resistance-type wires, they should measure about 1k Ohms per foot of length, and not more than 20k Ohms per wire.
     
  6. doodle-bug

    Thread Starter New Member

    May 14, 2008
    3
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    thank you very much for the help on the generator i checked all the items you listed and still no effect yet. am still trying and i`ll get this thing going. i found one spark plug wire that had too much resistance the points open and i have adjusted the gap to the specs. the coil must be bad i`ll have to get another one yhanks again doodle-bug
     
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