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Hot Rods Spark from coil issue??

Discussion in 'The Hokey Ass Message Board' started by rodderbilly, Feb 19, 2017.

  1. Hi all hambers....looking to try my spark plug issues(fouled plugs after low lo time)...i notate that that the wire from coil does a spark when i only rotate the key on ignition switch, i have a start push button to crank the engine,.....is normal that i have a spark only rotating the switch??i have a standard US11 ignition switch, i try another new switch but do the same thing when i rotate the key....i have a start button problem? .....this thing can causate my spark plug problem? i put small jets too but plugs became black in a couple of minutes....engine is a flathead ....ngk b4l plugs.............can you help me ?thanks
     
  2. Petejoe
    Joined: Nov 27, 2002
    Posts: 12,264

    Petejoe
    Member
    from Zoar, Ohio

    I believe I understand your question. ...
    Maybe someone who speaks Italian can translate your problem better.

    Your switch should provide current to the coil after the ignition switch is in the on position. Sounds like your wiring to the switch is incorrect.
     
  3. flathead4d
    Joined: Oct 24, 2005
    Posts: 898

    flathead4d
    Member

    Check the wire to the coil and from the coil to the distributor. If they are hooked up backwards on the coil the car will run but the spark will be weak..
     
  4. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA


  5. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

  6. Yes ...in the on position but 12v....not a spark,,the switch has 3 wire connectors,,,one for battery ,one to the coil and one for accessories,only the one for battery is signed the other 2 connectors are with no script, i try to interchange the 2 wires but no change....
     
  7. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    Do you have electronic ignition, or points? It's not uncommon for the coil to generate a spark when you turn the key from the "on" to the "off" position, because that mimics what happens when the points open.

    It is not the cause of your plug fouling issue. Black sooty plugs are caused by too much fuel. What carb/carbs do you have on it?
     
    henryj1951 likes this.
  8. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,214

    sunbeam
    Member

    If I understand your switch has 3 positions off accessory and one for the coil in one position only the accessory terminal should have 12v in the other both terminals should have 12 V. Do you have a condenser in the distributor?
     
  9. No condenser,,is a ready to run eletronic distributor from Bubba's,....yes my switch has 3 positions....
     
  10. I have 2 Stromberg 97s,,i low the jets to 37 from original 45.....
     
  11. What you mean for hooked backwards?
     
  12. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    If your coil has the polarity marked on it ( + and - ) the " - " terminal should be connected to the distributor. This assumes that your car is negative ground. Also note that coils from some of the positive ground cars built before the late 50's used coils that were would be marked backwards, even though the internal wiring is the same. In the drawing below, note that both the primary and secondary wiring have a common connection inside the coil. That common connection on most coils is marked " - ", and should be connected to the distributor.

    How does your car run? Starts OK, and runs under load without missing, or does it not run well?

    [​IMG]
     
    rodderbilly likes this.
  13. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    image.jpg

    "You test for correct polarity by hooking up a voltmeter with the negative lead to the plug terminal (which should be of negative polarity) and the positive lead to the block (which should be of positive polarity). Set the meter on the highest volt range. These connections remain the same whether you have a positive ground or negative ground electrical system. The secondary winding's polarity which we are testing is determined by the combined hookup of the battery and primary windings, so it may or may not match the battery's ground.

    Cranking the engine over (you don't have to start it) should show an upward swing of the voltmeter needle (don't be concerned with taking a reading). If the needle swings down off the scale, your coil is hooked up wrong. To correct, reverse coil primary leads. Do not worry about the coil markings (refer to definition #1).

    If you don't have a voltmeter, test by removing a plug wire from a plug and hold a plain lead pencil point in the path of the arc. A flair (hard to see) towards the plug shows correct polarity while a flair towards the coil shows reversed polarity."

    http://www.chicagolandmgclub.com/techtips/general/574.html
     

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