25hp kohler weak spark, missing

Discussion in 'Mechanic and Repair' started by mcambrose, Mar 15, 2005.

  1. mcambrose

    mcambrose LawnSite Senior Member
    Messages: 518

    I have a 25hp kohler that will intermittently run on one cylinder. The right plug has a weak yellow/blue spark. The front cylinder has a white and purple spark. Can this be caused by the spark advance module or does that problem have other symptoms? Any other suggestions?

    BTw I unplugged the ground wire (white) in the wiring harness and this did not improve the spark. I had been told to do this to make sure the safety switches weren't giving a weak ground somewhere, so that was ruled out.
  2. Redneck'n

    Redneck'n LawnSite Member
    Messages: 30

    i would have to say that it's the spark advance module.. they have a tester for that.. a local shop might have one and could test it.. if you have a shop you can trust not to tell you its bad just to sell you one.

    i dont know the part # of the tester right off hand. but Kohler has it.. and i dont have it here with me to get the # off of it.. i have relocated to Texas for work and left all my shop stuff in my shop in Louisiana.
  3. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    Here is the Kohler Special Tools listings

    Attached Files:

  4. Prairielandmower Service

    Prairielandmower Service LawnSite Member
    Messages: 8

    If it has never had the coils replaced and this is an older unit, you probably should replace coils and SAM unit. Some of the Kohler engines have a lifetime warranty on the coils, so it would be worth looking into. If you want any mor einfo, let me know
  5. mcambrose

    mcambrose LawnSite Senior Member
    Messages: 518

    Any idea how much a Kohler coil costs?
  6. wabenj

    wabenj LawnSite Member
    Messages: 1

    I would try disconnecting the ground wire to the spark advance module (not the white wire, but the ground directly to the module). If the engine runs after disconnecing this wire, then a problem is with the module (it may be a little hard to start but will run good). wabenj

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