kawasaki no spark

Discussion in 'Mechanic and Repair' started by bikerpbl, Jul 22, 2013.

  1. bikerpbl

    bikerpbl LawnSite Member
    Posts: 31

    i have a older scag 36'' walk behind that uses a kawasaki fb460v engine. i went out to cut my yards loaded it onto my truck when i went to drive it off it wouldn't start. i determined it doesn't have spark, iv tried new plugs, and i bought a new coil. before i buy any more parts i was hoping someone could help me out.
     
  2. BleedingGreen

    BleedingGreen LawnSite Member
    from SE MI
    Posts: 165

    Is the new coil on? Check all safety switches and connections. Bypass them to test the switch itself. Sometimes rain or water from washing them causes electrical problems till it dries out.
     
  3. bikerpbl

    bikerpbl LawnSite Member
    Posts: 31

    Yes the new coil is installed and gapped to the thickness of a business card. There are two wires that go to the coil that connect into one. One wire goes to the blade engagement switch and then to the key the other goes to a little silver box that is the igniter I'm pretty sure. I unplugged the wire that goes to the switch and key and still don't have spark. Does that mean the igniter is bad?
     
  4. BleedingGreen

    BleedingGreen LawnSite Member
    from SE MI
    Posts: 165

    It's possible that the igniter module went bad. We used to call them chiclet chips (cause they look like a piece of chiclet gum). However it's been my experience that they usually start acting up i.e. causing the motor to spark at the wrong time thus causing the motor to run bad, backfire, etc. rather than just stop totally out of the blue, but I suppose could happen. I just personally never had it happen that way.

    I can only go off what you have told me, but there should be a number of safety switches and components that would cause the ignition to be cut off. This includes but is not limited to a key switch, neutral position switch, parking brake switch, operator presence switch, blade engagement switch, etc. If any of these are bad or have a loose connection it's going to cut power to the ignition which = no spark. Without having the mower in front of me I can only explain how these switches work and hope you can thoroughly test EVERY one of them prior to replacing the ignition module.

    Unplugging wires is generally NOT the way to bypass a switch. The way these switches work, especially on older mowers is the switch either opens or closes the circuit. Ever see a kill switch on say a trimmer that is either a "0"or "I" instead of "on/run" or "off/stop"? The "O" is and open circuit which mean power IS NOT flowing. The "I" is a closed circuit which means power IS flowing or a complete circuit. Most of the time a switch interrupts or opens the circuit on a wire with power running through it and this will stop the flow of electricity. Therefore to bypass a switch you need to disconnect the wires from the switch itself and directly connect them together. This will ensure that you are creating a closed circuit allowing voltage to flow. Simply unplugging a wire generally creates an open circuit, which is like having a faulty switch, and not allowing the voltage to flow. You cut the voltage it will generally cut the ignition.

    I tell you this for the purpose of testing switches only if you do not have access to a test light, volt meter, multimeter, etc. I do not condone bypassing switches for the sake of bypassing them for normal operation of your equipment. But before throwing a new ignition module on the mower check each and every one of these switches including the key switch by bypassing them ONE AT A TIME. Trace every wire going to and from these switches to make sure they are making a good connection and not melted or something. Also make sure the new coil spark plug wire has the metal clip that snaps onto the spark plug inside the boot and that it "clicks" over the spark plug. Then if and only if you have done all of the above try a new ignitor. My guess is it may be more simple than that.
     
  5. bikerpbl

    bikerpbl LawnSite Member
    Posts: 31

    Thanks for your help so far. Yea I have a DMV not a test light though. My machine has a blade engagement button type switch a plug that goes to the trans and the key. How would I go about testing them?
     
  6. newenglandguy

    newenglandguy LawnSite Member
    Posts: 7

    Best way to test the switches is with an ohmmeter. If you can isolate the switch from the circuit then simply connect a lead from ohmmeter to each side of switch and measure. Of switch measures zero ohms than switch is closed, so know activate/depress switch and then take reading. The switch would read infinite resistance mening on open - or basically the inverse of this scenario. If you can't isolate the terminals than read cross and then activate switch. The readings will be similar. Should go from shorted, or zero ohms and then to open, orr infinite resistance. Or the reverse of this, again when you toggle the switch to its other position.
     
  7. bikerpbl

    bikerpbl LawnSite Member
    Posts: 31

    ok thanks for the help ill try testing the switches.
     
  8. bikerpbl

    bikerpbl LawnSite Member
    Posts: 31

    Well I tried a new igniter cleaned all my switches and I finally have spark, it's running better than before. Thanks all the posts.
     

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