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shutting off your lazer

Discussion in 'Lawn Mowing' started by scott's turf, Jul 29, 2002.

  1. scott's turf

    scott's turf LawnSite Senior Member
    from NH
    Posts: 949

    When you shut off your lazer do you thottle down first. I was doing this but found that when I did shut it off the machine would always backfire. What do you guys do?
  2. 65hoss

    65hoss LawnSite Fanatic
    Posts: 6,360

    I was having the same problem with mine in the past. Here is what I started doing...

    When I load on the trailer I turn the fuel to the off position. I let it run itself out. This does 2 thing, 1st it doesn't backfire anymore. Secondly, it allows the motor to cool down before shutoff. Air cooled motors get their cooling from running. Let it go at idle while the fuel is running out and it gets less friction, air is moving, oil is moving, all of which helps cool the motor.
  3. SIG

    SIG LawnSite Member
    Posts: 188

    If you guys have Kohlers, read your owners manual. You should shut the mower down in 3/4 throttle position. Will eliminate the backfire and run-on problem. It's right there in the owners manual.
  4. Pro-Cut Lawns

    Pro-Cut Lawns LawnSite Member
    Posts: 71

    I load mine on the trailer when Im finished, leave it idling, put up the gate, start my trimmer, then shut the mower down. Once it idles in that amount of time before shutting it off it wont back fire. I would rather do that than shut it down at 3/4 throttle.
  5. bubble boy

    bubble boy LawnSite Bronze Member
    Posts: 1,020

    hoss, is that at full throttle? i have a toro with a kawi engine(12 HP? i don't know off hand) that will backfire unless i throttle down before shut off. i never tried what you're saying, but i would have thought letting the fuel line drain at full throttle would still result in the back fire, since the engine is still going pretty strong.

    is this normal? doesn't happen on our ferris with the kawi.

    and is it harmful to the engine?
  6. 65hoss

    65hoss LawnSite Fanatic
    Posts: 6,360

    At idle.
  7. AltaLawnCare

    AltaLawnCare LawnSite Senior Member
    Posts: 962

    After I unload, I always close the gate on the trailer. So when getting ready to load,..
    I idle down,
    Set the parking brake,
    Turn off the fuel,
    Get off and lower the gate, fold over the discharge chute,
    Idle up to 3/4 throttle, drive up on the trailer,
    Lower the deck all the way down, idle down to 1/2 throttle,
    Set the brake, then shut it off.
  8. scott's turf

    scott's turf LawnSite Senior Member
    from NH
    Posts: 949

    I have a 23 hp kaw. Hoss when you do this do you have to choke it to start it at every job? What damaged is cause by shutting off a hot engine? Is it going to cool to quickly and cause a thermal contraction problem?
  9. Runner

    Runner LawnSite Fanatic
    Posts: 13,496

    With the 20 hp Kohler Magnum, I would always let it idle down for a minute or so while I did the gate and such. Otherwise, it wouldn't backfire when I shut it off, but when I would start it back up again. Even after it sat for awhile. With the Command though, I just idle it down for a few seconds and shut it off. It's fuel injected, so there isn't really any difference.
  10. 65hoss

    65hoss LawnSite Fanatic
    Posts: 6,360

    That is the same motor I have. Yes, you choke it at the next job. Fires right back up.
    The 1st thing that an air cooled motor does when you shut it off is increase the heat. It gets hotter before it cools down. Nature of metal. It doesn't hurt anything, because it doesn't cool down that much.

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