Only get spark when turning switch off

Discussion in 'General IH Tech' started by Randall Barringer, Oct 28, 2019.


  1. Randall Barringer

    Randall Barringer Y-Block King

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    I am working on getting the military Scout running and I´m having an issue.
    I only have spark from the coil when I turn the ignition switch off.
    No spark while cranking.
    I haven´t looked into the wiring other than cleaning the connection at at the ballast resistor.

    Where should I begin?

    Thanks
     
  2. walkersscout

    walkersscout High Wheeler

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    Do you have a wire from the coil to the starter solenoid?
     
  3. Randall Barringer

    Randall Barringer Y-Block King

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    I'll confirm, but I'm pretty sure it's there.
    Thanks

    Sent from my SM-G955U using Tapatalk
     
  4. RinTX

    RinTX High Wheeler

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    I guess I’d start at the switch? Wires connected to wrong positions at the switch?
     
  5. Jeff Jamison

    Jeff Jamison Lives in an IH Dealership

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    Solenoid on the starter has a contact that sends power to the coil while cranking/ingaging starter,This is the R terminal on the starter,check there for power,if not clean contactor/replace solenoid .If power there check wire to coil/coil side of the ballast resistor .
     
    Last edited: Oct 28, 2019
  6. Randall Barringer

    Randall Barringer Y-Block King

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    Thanks, everyone. This gives me good places to start.

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  7. Bob BMW

    Bob BMW Binder Driver

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    As long as we are guessing, my guess is points stuck together or the wire from the points side of your coil to the points in your distributor is shorted to ground somewhere.

    You are getting power to the coil with the switch on. When you turn the switch to off you get a spark. This happens because one side of the coil is grounded and you remove power from the other side. Kind of sorta the opposite situation of normal operation.

    Good luck.

    Bob
     
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  8. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    The starter solenoid 'S' terminal does not feed the coil. That terminal receives power from the ignition switch when turned to the Start position, which then causes the starter motor to engage. It has nothing to do with coil function. The solenoid 'R' terminal on the other hand, is a resistor bypass feed to the coil, which does momentarily supply full battery voltage to the coil only while the starter is cranking. The primary power feed to the coil is supplied from the ignition switch and it should be energized in both key switch ON and Start positions. You can rig a temporary jumper directly from the battery POS to the coil which will bypass the switched feed to the coil. Just don't leave that jumper connected with the engine stopped, and don't run the engine for too long on that jumper either. The coil is also not connected to chassis ground. The negative coil terminal is connected to the breaker points inside the distributor.
     
  9. Jeff Jamison

    Jeff Jamison Lives in an IH Dealership

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    OOPs I meant R,will go back and fix.
     
  10. Randall Barringer

    Randall Barringer Y-Block King

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    This was the issue.

    It's not running yet, but I have spark when I crank it.
    Thanks

    Sent from my SM-G955U using Tapatalk
     
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  11. Bob BMW

    Bob BMW Binder Driver

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    Very good Randall. One step at a time and you will get there.

    Thanks for reporting back too.

    Bob
     
  12. Randall Barringer

    Randall Barringer Y-Block King

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    That middle wire was screwed down with the others.
    I'm not sure where it belongs. These delco distributors are tough to analyze because you can't see anything. When I removed it I got spark while cranking. I'll dig deeper tomorrow. [​IMG]

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  13. Bob BMW

    Bob BMW Binder Driver

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    That middle wire that was screwed down with the other two screwed you. The other two wires are: One is from the points terminal on your coil and the other one is from the condenser which is located inside your distributor. That third wire is a ground wire. Since it was connected to the other two, it was grounding your coil, which I suggested in my first reply, was causing your odd symptom.

    It has been many many years since I messed with a distributor of this type on my Scout. My manual doesn't show a very good picture of where the ground wire connects but I believe, from looking at your picture and my service manual, it goes under the points mounting screw that you can see under the black 'third' wire. Remove the screw and internal star lock washer and then clamp the wire to the breaker points plate with the screw and it's lock washer. The other end of this ground wire is clamped down with one of the vacuum advance canister mounting screws.

    Bob
     

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