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Old Laser Z Problems

Discussion in 'Mechanic and Repair' started by schumany, Jun 1, 2006.

  1. schumany

    schumany LawnSite Member
    Messages: 14

    I cut the lawn at my church with an older Laser Z with a Kohler Command 25 HP engine. It was in tough shape when I first started using it, but I've had it fixed up. I now have a mulch kit on it and a high-capacity air filtration system. My problem is, after cutting for a coouple of hours, it starts to konk out on me. I try to keep the cooling areas clean and scrape out the deck before each run. It has new oil, spark plugs, fuel filter, etc.

    If anyone has any ideas, I'd appreaciate it.


  2. DEEJ

    DEEJ LawnSite Member
    Messages: 230

    Move this to the Mechanic and Repair area and you will get some answers from the experts.

    The first thing I would suspect is a bad coil or ignition module - not sure if they are separate or integrated on this engine. Once the engine heats up sufficiently, the coils or ignition module slowly get hot to the point they won't function properly (a common problem as they age). Once everything cools down they work fine again. The solution is simply replacing them. That is the first place I would look given the symptoms you describe.

  3. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Messages: 11,087

    Yep... sounds like an ignition issue to me too.

    Probably a coil in the early stages of going out.

    Since it is an older 25hp Kohler, also be sure to give it a good inspection around the head gasket area while you have trouble on the brain.
  4. khouse

    khouse LawnSite Bronze Member
    Messages: 1,465

    konk out is not enough info for me. tell us exactly what that means to you.
  5. thecrankshaft

    thecrankshaft LawnSite Member
    Messages: 172

    It would be odd for both coils to fail at the same time. These engines run pretty good on one cylinder.

    Spec number would be helpful - does this 25 have spark advance?
  6. schumany

    schumany LawnSite Member
    Messages: 14

    Thanks guys. Sorry if I posted in the wroung area. Konking out means that it starts losing power, then starts to stutter, then cuts out altogether.

    I don't know if it has spark advance, it's not mentioned in the manual.

    As far as I know, it has only one solenoid. It really sounds like that's what's going out. It only has 350 hours on it, but the bought it in 1997!

    Once again, thanks so much!
  7. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Messages: 11,087

    Did you get it taken care of?

    If not, just so you know, when a coil starts to go, sometimes it will start out where it's doing fine, and after it gets hot it still makes 'fire' and often will continue to. But it continues to degrate. Athough it will sometimes still make fire, it's not making good fire.

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