Exmark lazer Z Engine Trouble

Discussion in 'Mechanic and Repair' started by pcpro15, Jun 28, 2006.

  1. pcpro15

    pcpro15 LawnSite Member
    from PA
    Posts: 17

    I got an exmark lazer Z (kohler engine 25hp air cool) and all of a sudden it wants to play games. Sometimes when at full throttle with blades on, the engine pitch will switch back and fourth between normal and muffled. When the engine sounds muffled, it loses major power and RPM's and makes it almost impossible to cut grass with. Then there are those other times when it wants to run perfect for about a stripe of grass or two and then its back to spitting and sputtering. Air filters clean, Cleaned spark plugs, oils good, new gas. I mean I went over just about everything I could think of with out buying new parts. When the tractor ran good before this started happening, the muffler used to get very hot very quickly. After 2 minutes, the muffler is unbearable to touch as you might expect but also becomes close to a cherry red around 5 or so. This leaves me to believe it is running lean??, but the oil also becomes unbearably hot also. It doesn't seem like the oil is staying cool and if you open the yellow cap that you pour oil in, you see steam come out. I think the tractor is probably on it's way out, but I can not even come close to afford a new tractor at this point. Any suggestions would be appreciated.

    Thanks in advance,
    pcpro15
     
  2. TLS

    TLS LawnSite Fanatic
    Posts: 7,940

    Fuel filter?

    Gas tank vents?

    How many hours?
     
  3. FIXDISS

    FIXDISS LawnSite Senior Member
    Posts: 445

    When you cleanned plugs did you notice any black carbon deposits or oil on plugs ? From what I have read on other posts there may be a head gasket issue . Also have you drainned float bowl to see if there may be some water or sediment in it ? Need to also check blower housing and cooling fins for debris or blockage.And last check the muffler and exhaust for damage or blockage.Post model #'s and I'm sure someone here can give you some other advice.
     
  4. TLS

    TLS LawnSite Fanatic
    Posts: 7,940

    Yeah....I've heard mufflers go, but usually they just get loud.....but if a baffle broke loose, it could cause a big restriction that could come and go.
     
  5. pcpro15

    pcpro15 LawnSite Member
    from PA
    Posts: 17

    The spark plugs had some carbon residue on them even after I cleaned them with WD-40. The engine has around 1600 hrs. Fins are clean. Gas cap vents are good because it is happening on both tanks. I took the muffler off because the baffles had been replaced before. The muffler is still off and problems continue. I am not sure of the serial number at this point because the mower is outside. The model number is LZ25KC604. I purchase this mower 2nd hand with 1300 hrs. on it and have had it for about 5 years now. I am going to look into a new fuel filter tomarrow morning.

    Thanks everyone for the imput,
    pcpro15
     
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    Read the 5th thread from the top in this forum, Then post the engine numbers.......
     
  7. pcpro15

    pcpro15 LawnSite Member
    from PA
    Posts: 17

    I appreciate your willingness to help Restrorob, but I do not have access to the mower at this moment, so I gave the next best thing. The model number. The engine was made probably around 2001 although I am not positive. I know where that number is at, and when I go out in the morning, I will be sure to get the number for you.

    Thanks in advance,
    pcpro15
     
  8. FIXDISS

    FIXDISS LawnSite Senior Member
    Posts: 445

    Hey Rob, haven't talked to you in a while. Looks like site administrator is giving you a hard time by enterring posts and making the "Read before posting" msg drop down further all he time. Ha Ha. Have really picked up a lot from your replies to guests here. Thanks.
     
  9. pcpro15

    pcpro15 LawnSite Member
    from PA
    Posts: 17

    The serial number for my tractor is in the 190,000 range.

    Exmark Operator Manual
    Exmark Parts Manual

    Don't Know if those links are necessary, but I assume that is what you need the serial number for.

    Thanks in advance,
    pcpro15
     
  10. pcpro15

    pcpro15 LawnSite Member
    from PA
    Posts: 17

    The Model number for the engine is CH25S
    The Spec Number for the engine is 68606
     

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