Kohler 15hp backfire

Discussion in 'Mechanic and Repair' started by Lawn Man 5, May 18, 2002.

  1. Lawn Man 5

    Lawn Man 5 LawnSite Member
    from Ohio
    Posts: 36

    Every time i shut my motor off it backfires, (it probely has about 100 hours on it). Is this normal. If i let it idle down it won't. Will it hurt the motor if i let it backfire.

    Thanks
     
  2. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    If your muffler is thin or rusty it can blow a hole in it. You can fix your problem by shutting the engine down at 3/4 to full throttle. Try it and let me know. It won't hurn anything.
     
  3. Lawn Man 5

    Lawn Man 5 LawnSite Member
    from Ohio
    Posts: 36

    That is when it backfires, if i let it idle for about a minute it won't backfire. When I go from full throtle or 3/4 and shut it off it really bangs. But I like to just turn it off.
     
  4. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    Each engine - even the same engines seen to have their own way of starting and running. If yours wants to be at idle for a minute before it shuts down then you may have to keep doing that. You can also check to see if your engine is running hot by chaff build up in the engine.
     
  5. Bo Jack

    Bo Jack LawnSite Member
    from midwest
    Posts: 28

    I have the 14 Hp with 380 hrs and it does exactly the same (backfire). Use the same procedure as you for shut down.
    Guess its the nature of the beast
     
  6. catsnglf

    catsnglf LawnSite Member
    Posts: 2

    I was told by a dealer that the Kohler will backfire unless you let it idle for a minute or two before shutting down. They didn't explain why, just that they do if you turn it off without idling. My 16 HP did it too, but now that I let it idle it doesn't.:rolleyes:
     
  7. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Posts: 342

    I recently emailed B&S asking a question about my riders engine backfiring when shutting down, and he said to let the engine idle before shutting it down, and you should have no more problems.:)
     
  8. scottb

    scottb LawnSite Senior Member
    Posts: 408

    Its a good practice to let most any engine idle before you shut off.
     
  9. Jman

    Jman LawnSite Member
    Posts: 217

    If your engine has a fuel shut off solenoid on the carb, shut it off at 3/4 to full throttle. If no solenoid you will need to let it idle for a minute or two to cool the exhaust system down. To let them run at wide open with NO load will actually cool the engine down but not the exhaust system. Remember these are air cooled engines. When we let them idle the fan doesn't blow as much air past the engine and doesn't cool it properly. The backfire is caused by unburned fuel hitting a hot spot in the muffler and igniting it.
     
  10. Jman

    Jman LawnSite Member
    Posts: 217

    If your engine has a fuel shut off solenoid on the carb, shut it off at 3/4 to full throttle. If no solenoid you will need to let it idle for a minute or two to cool the exhaust system down. To let them run at wide open with NO load will actually cool the engine down but not the exhaust system. Remember these are air cooled engines. When we let them idle the fan doesn't blow as much air past the engine and doesn't cool it properly. The backfire is caused by unburned fuel hitting a hot spot in the muffler and igniting it.
     

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