27 kohler sputters at full throttle

Discussion in 'Mechanic and Repair' started by scottishmaximus, Oct 3, 2006.

  1. scottishmaximus

    scottishmaximus LawnSite Senior Member
    from ohio
    Posts: 286

    I have a 27hp vertical shaft kohler command on a husqvarna zero turn that sputters under load at full throttle. It really slows down, not just an occasional miss. I can back it to about half throttle with the blades on and go easy with the hydros and it will maintain speed.

    Oil fine.

    Gas in tanks, valve open.

    Runs the same with or without air filter. Air filter gauge shows ok.

    I checked the spark plugs, one was blacker then the other; gapped and replaced both.

    Checked coil gap on flywheel (when doing a previous repair I gapped it to about a business card then found out it had to be precise on this model. regapped it to spec using two feeler gauges).

    Still has almost complete loss of power at high speed or when under load.

    Any ideas??
     
  2. hartmas

    hartmas LawnSite Member
    Posts: 71

    My 23 hp Kohler on my Exmark Lazer HP does exactly the same thing......
     
  3. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Can you apply choke about 1/2 to 3/4 of the way when it happens and it smooth out?
     
  4. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Posts: 1,164

    They were both black or one was really white and the other was black? I have seen intake gasket leaks that make the units loose power on the one cylinder with the leak.
     
  5. scottishmaximus

    scottishmaximus LawnSite Senior Member
    from ohio
    Posts: 286

    I tried using some choke and that made it worse. Starting fluid directly into the carb while it was running and sputtering made it worse.

    I tried spraying wd 40 (ran out of starting fluid) around the intakes and there was no change. I was thinking an intake leak as well.

    Both spark plugs were black. One noticeably blacker.
     
  6. FIXDISS

    FIXDISS LawnSite Senior Member
    Posts: 445

    While under load did you try turning the fuel mixture screw in til it begins to slow then back off 1/4 turn or so til it smooths out ? Sounds like it is too rich .
     
  7. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Is the choke butterfly/flap opening FULLY ? The cable could have slipped in the hold down clamp.
     
  8. FIXDISS

    FIXDISS LawnSite Senior Member
    Posts: 445

    That was gonna be my next question as to whether this thing has a separate choke cable or if the throttle plate/cable was in proper position.
     
  9. scottishmaximus

    scottishmaximus LawnSite Senior Member
    from ohio
    Posts: 286

    I haven't touched any carb adjustments.

    The choke is a separate cable and it is opening and closing all the way, as is the throttle.

    I wonder if the a coil is going bad since i had the gap larger then spec. Any way to check?

    I also checked the flywheel key, it's ok.
     
  10. FIXDISS

    FIXDISS LawnSite Senior Member
    Posts: 445

    Try adjusting carb like I suggested under load and see if it makes a difference. Do you see any black smoke under load ?
     

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