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Kohler engine pops

Discussion in 'Mechanic and Repair' started by lawnandl, Oct 16, 2009.

  1. lawnandl

    lawnandl LawnSite Member
    Messages: 78

    I have a walker with a 20hp kohler engine and recently the mower started popping during use, with the blades on or off. Sometimes the engine will run fine for the 1st five minutes or so and then it starts. I was wondering if it may be the valves? the fuel line and filter have been replaced, along with the air filter and plugs. Any suggestions please?
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Sounds like you may have answered your own question, I would check into the valves/guides/seats. A compression test is better than nothing but a cylinder leak-down test tells all.
  3. lawnandl

    lawnandl LawnSite Member
    Messages: 78

    Thanks, would you happen to know the correct valve clearance?
  4. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    What's the model AND spec numbers ?
  5. AzLawnMan

    AzLawnMan LawnSite Senior Member
    Messages: 409

    Change out the plugs, air filter and gas filter. See how it runs, if the spark plugs foul out again then you may have a problem with motor. If the motor is bad, in my experience then those plugs should only last a few hours before the foul out again. Start with that and then go from there. If you do all that and still have a problem, drop it off at your local certified dealer and have them look at it.
  6. DT Lawn Care

    DT Lawn Care LawnSite Senior Member
    Messages: 850

    Are you a MORON??? Check the original post, he replaced everything you specified, and he is looking into the valves, meaning he knows more that the jackshit that you know about motors.

    Just drop it off at the dealer, pay whatever for whatever they fix, who cares huh. Mechanics and Repair section is for people who actually know something about fixing mowers themselves, so ya you might not want to post here.

    And BTW, yes I too would look into the valves.
  7. lawnandl

    lawnandl LawnSite Member
    Messages: 78

    ok, and well said. Back to you Restrorob, the model and spec numbers are, Kohler CH20s 64554...
  8. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    This engine has hydraulic lifters therefore the rockers are non-adjustable, A compression test may tell which cylinder is at fault but a leak-down test surly would. Once the faulty cylinder is identified you may have to perform a tear-down inspection of the valves/seats and guides.
  9. East Coast Lawn Choppers

    East Coast Lawn Choppers LawnSite Member
    Messages: 134

    Agree 100% with restro we replace a dozen or more bad valves each year, some broke some burnt and a few that the seat fell out. A leak down is best, if you don't have access to one do a compression test to get to the bad cylinder. But to go to all the trouble of doing one head do them both.
  10. starry night

    starry night LawnSite Gold Member
    Messages: 3,263

    Leak down test gets my vote, too. (Do I get a vote?:) )

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