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Won't start!

Discussion in 'Lawn Mowing' started by accuratelawn, May 4, 2004.

  1. accuratelawn

    accuratelawn LawnSite Senior Member
    Messages: 922

    Little help.
    25 Kohler on Lazer Z. 1800+ hours.
    New plugs and battery. Fuel pumps works and all filters in good shape.
    Problem... no spark when testing spark plugs. Motor turns over, but will not start.
    Any ideas?
    Thanks in advance.
  2. mastercare

    mastercare LawnSite Senior Member
    Messages: 289

    Check the solenoid. The lazers actually have 2 of them. the obvious one is one the starter. The second one doesn't even look like a solenoid. It's on the battery cable between the battery and starter. It's black with two posts sticking right up. Mounted on the frame. They're about $15, I've replaced 2 of them now. Although, if the engine is turning, maybe that's not it. Good place to start though. Try using a jumper cable from your battery to your starter. If it fires, then the solenoid (which you're bypassing) is probably your problem.
    Hope this helps.
  3. AirCooled

    AirCooled LawnSite Member
    Messages: 30

    As goofy as it sounds, the problem may be as simple as the battery connected backwards. If thats not the case, first thing you need to do is determine if the problem is in the engine or the Lazer wiring. The Kohler's use a white wire for ignition "kill". Look for the harness plug coming out of the engine and disconnect the white wire. If you have spark, the problem is on the Lazer side of the harness. If still no spark, then the problem is on the engine side.
    The 25hp uses that spark advance and needs power when the key is in the "ON" and "Cranking" positions. The easiest place to check power is at the carburetor fuel solenoid. There are two diodes in the engine harness and if one goes out you will only have power in one of the two key positions.

    Hope this helps.
  4. specialtylc

    specialtylc LawnSite Bronze Member
    Messages: 1,656

    Ignition coils are bad.
  5. dishboy

    dishboy LawnSite Fanatic
    from zone 6
    Messages: 6,116

    How did you determine that?

    I would check that all your conections for safety switches[like blades, nuetral for wheel drive etc.] are connected and making good contact as well as all wiring leading from ignition switch to ignition module, a 12 volt test lamp may be of some help in checking this.
  6. specialtylc

    specialtylc LawnSite Bronze Member
    Messages: 1,656

    Well my mowers wont crank over if the saftey switches are acctivated or not working. 99.9% probabilty its the coils.
  7. Zachary52902

    Zachary52902 LawnSite Member
    Messages: 38

    I just had the same problem with my bobcat zt200. i replaced the ignition coils and it fired right up. I would say it is the ignition coils. That would be the first place i would start.
  8. DLCS

    DLCS LawnSite Platinum Member
    Messages: 4,386

    Right, most safety switches keep the motor from turning over. I would replace the spark plugs then check the coils.
  9. AirCooled

    AirCooled LawnSite Member
    Messages: 30

    Why does everybody insist on replacing parts at random until the thing works? There is a systematic way of finding the problem but most people rather listen to what worked for one person and hope it works on his. I must laugh at coils because in most cases I think it would run on at least one coil being a twin cylinder.
    I listed a systematic way to find the problem. Try it, its really not that difficult.
  10. Goodguy001

    Goodguy001 LawnSite Member
    Messages: 44

    Aircooled is correct.
    First check voltage to eng. should be at least 7.2v in the run and start poss. at the double red lead at eng connector. If thats good, pull the cover, check air gap. check secondary resistance to module (coil) 1 lead to laminations and other to sark plug term. resistance should be 7900-18400 ohms. either above or below then you know coils are bad. But both at same time a little odd
    good luck

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