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ignition switch question

Discussion in 'Flat Fender Tech' started by 51M38, Jul 12, 2006.

  1. Jul 12, 2006
    51M38

    51M38 New Member

    HAWAII FOR NOW,...
    Joined:
    Jun 13, 2006
    Messages:
    18
    I have a 51 M38 that has been converted to a 12v system. The ignition switch in it is from Napa. I can crank the engine all day long but it will not start until I let go of the key. It has posistions for " acc., off, & start"
    Is there another ignition switch that anyone has used that they recommend or have any ideas. It's like a guessing game when to let go of they key and it usually take 2 or 3 times to get it started. Thanks for your help out there...

    Josh
     
    51M38, Jul 12, 2006
    #1
  2. Jul 12, 2006
    Canadian 62

    Canadian 62 Member

    Kelowna BC
    Joined:
    Jul 6, 2006
    Messages:
    61
    I have opened the civilian manual and I can't see on the diagram how they put power to the ignition while starting. But it sounds like you have a non stock switch now anyway.

    A dirty fix would be to have an extra push button switch with one side through a fuse to the battery or a positive source and the other side to the ignition coil. When you turn the key on the ignition switch you have now to start...hold in the new button and the engine should fire. Release from the start position and the Acc will take over powering the ignition system and you should be able to release the new button.

    I don't know how good you are with relays but the same can be done automatically with one of them. When you turn to the start position it powers the relay closing the contacts powering the ignition system for only the time the key is turned to start.
    Both ways above isolates the power from keeping the starter running when you turn back to Acc. They are also a five buck fix and you don't have to fool with the starter switch you have already.

    Hope this gets you back on the road quick.
    Ed
     
    Canadian 62, Jul 12, 2006
    #2
  3. Jul 12, 2006
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
    Joined:
    Nov 6, 2002
    Messages:
    4,275
    An easily overlooked item when wiring up the ignition primary circuit is the jumper wire that powers the coil when cranking. From your description, it sounds liek this might be your problem.

    Normally, the ignition circuit gets 12v (+) from the "ON" stud on the ignition switch. Along the way, the 12v (+) passes through the ballast resistor to knock it down to ~8 volts or so. This keeps the points from frying in short order. Depending on whether or not the coil has an internal resistor, you may or may not have a ballast resistor. The coil should be marked in some way to indicate this.

    Now, here's where it get's interesting: You should have another wire coming from the ignition switch "START" stud, running up to the (+) stud on the coil. Sometimes this can also be a wire run from the small terminal on the starter solenoid that receives 12v (+) only when the key is in the START position. (Only one of these is needed!) The pupose of these wires is to provide a slightly higher coil voltage while cranking, in order to help fire the engine over. Once you release the key back to the "RUN" position, the voltage should drop back to ~8v and the engine is quite happy there.

    Clear as mud?
     
    w3srl, Jul 12, 2006
    #3
  4. Jul 12, 2006
    51M38

    51M38 New Member

    HAWAII FOR NOW,...
    Joined:
    Jun 13, 2006
    Messages:
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    thanks to both of you. it does have have a coil with internal resistor. i'll check those wires and see if it look like what you were sayin. hopefully its somethin as easy as you were sayin NEMO.
     
    51M38, Jul 12, 2006
    #4
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