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Discussion in 'eXmark' started by Quality Lawn Care, Jul 2, 2002.

  1. Quality Lawn Care

    Quality Lawn Care LawnSite Member
    Posts: 45

    I have a 52" Lazor HP with a 23 hp kol. on it. I just bought it this spring and have about 50 hours on it. The problem is it has back-fired after turning it off ever since I picked it up. It also smokes a lot when I first start it (is this normal?). Any help you could give me would be great.
  2. Jman

    Jman LawnSite Member
    Posts: 217

    Try shutting it off with the throttle at least half open if not wide open. The carb has a fuel shut off solenoid that only shuts the fuel flow off in the idle circuit, not the high speed circuit. It's totally backwards of what we have been taught for years, but it should work.
  3. TLS

    TLS LawnSite Fanatic
    Posts: 7,940

    My old 25hp Kohler would cough, bang, smoke, sputter, sound like a VW bug, and blow head gaskets like they were going out of style. Backfiring was always an expected occurance.

    But just this year, I tried what seemed like wouldn't work. I forgot who told me this, wether it was Terry or Dustin over here, or a "civilian" :p in the regular board!

    Let it idle for about 1 or 2 minutes, then just as your flick the ignition off, jab the throttle up to 1/2. Never knew this when I had the Kohler, but for my LC Kawi, it works great and it NEVER backfires when I do this.

    I guess it has something to do with equalizing intake and exhaust pressures.

    Good Luck!
  4. gogetter

    gogetter Banned
    Posts: 3,256

    You gotta let it cool down before shutting it off. Just a minute or so.
    As far as the smoking, someone else will have to answer that one.
  5. eXmark

    eXmark Manufacturer / Sponsor
    Posts: 4,258

    Hey Quality Lawn Care,

    Thanks for the post. When you turn it off, where do you position the throttle - full, 1/2, or idle? Have you tried multiple throttle settings? If so, do it always backfire no matter where you position the throttle? Is it more frequent or less at different positions?

    Try this. Place the throttle halfway between the "slow" and "fast" positions. Let the motor run for at least 15 seconds, and shut the engine off. See if this doesn't help. The backfiring problem is not really detrimental to your engine. It's just more of a nuisance than anything.

    You also said that the engine smokes. What color is the smoke when you start it up - white or black? How long does it smoke for? Do you choke the engine every time you start it up?

    It's normal for it to smoke a little the first time you fire it up of the day, but it should only smoke for a few seconds. Create another post or e-mail me at dustin.schwab@exmark.com with the answers to my questions.

    Thanks again,

    Exmark Customer Support
  6. Bonuts

    Bonuts LawnSite Member
    Posts: 5

    I have the same back-firing problem, but its on a brand new Metro 36 with a 12.5 Kawasaki (less than 10 hours). For me, too, it's been back-firing on shut-down ever since I picked it up. But I can't do what you suggest because the shut off is on the throttle. Any suggestions for me?
  7. eXmark

    eXmark Manufacturer / Sponsor
    Posts: 4,258


    On all models with a throttle controlled shut off it often helps to let the unit idle for a short period of time (say 30 seconds) before shutting it down. This should reduce the number of backfires but may not completely eliminate them. If you see no improvement in the backfiring after idling the mower down for a short period of time please have it inspected by your Exmark or Kawasaki dealer.


  8. Old Guy

    Old Guy LawnSite Member
    Posts: 59

    My 52" Lazer HP backfires also. I just turn the gas off as I start up the ramp, idle it down when I have it in the proper position on the trailer and then let it run out of gas (30-60 seconds). It usually runs out about the time I get the ramp up and get the trimmer ready. Then I turn the gas back on, turn the ignition off and it's ready for the next time. Don't forget to turn the ignition off! I forgot on the last job on a Friday and had a dead battery the following Monday. :eek:
  9. shawns mowing

    shawns mowing LawnSite Member
    Posts: 11

    I bought a hp 52 deck kol 23 new this year it back fired to. i tried adjusting the carb but with no luck . i then tried lowing the idle speed of the motor that took care 95% of the back fires. let the motor get completly warmed up befor lowering the idle. I also have problems with lound lifter noises but found out from the kohler company that air is getting in #1 cyclinder liffters and not leting it pump up all the way on the horazal motors. kohler said they have a kit that fixes the probelm.
  10. MikeLT1Z28

    MikeLT1Z28 LawnSite Bronze Member
    Posts: 1,732

    65hoss found that idling all the way down and cutting the fuel will let it cool down and shut down with no backfire. just remember to turn off your key after.

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