(Exmark) Kohler 20 hp Command smokes at startup, accelerating and decelerating?

Discussion in 'Mechanic and Repair' started by HenryB, Nov 24, 2012.

  1. HenryB

    HenryB LawnSite Bronze Member
    Posts: 1,828

    Title says it all lets out white some on these three occasions. Once running no smoke
     
  2. Monroe74

    Monroe74 LawnSite Senior Member
    Posts: 322

    Sounds like leaky valve seals
     
  3. HenryB

    HenryB LawnSite Bronze Member
    Posts: 1,828

    Hard to repair?
     
  4. CowboysLawnCareDelaware

    CowboysLawnCareDelaware LawnSite Senior Member
    from DE
    Posts: 555

    How many hours on the engine, you may want to rebuild the motor?

    Michael
     
  5. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    How much oil is it using..?? What do the sparkplugs look like..??
    The rule of thumb is....
    If it smokes while throttling up....its bad rings..
    If it smokes when throttling down...its a leaky head gasket...
    Check your compression....normal is 180 psi....
     
  6. Monroe74

    Monroe74 LawnSite Senior Member
    Posts: 322

    Valve seals are pretty easy to do you will need to remove the valve springs from the head one at at time but in doing so use compressed air to keep the valve in the closed position. With time and exp this should take half hour each cyl
     
  7. Monroe74

    Monroe74 LawnSite Senior Member
    Posts: 322

    The reason I say it's valve seal is because you said it happens at start up. Then accel till it warms up. Oil collects in the head then drains into cyl when it starts it burns the oil.
     
  8. ericg

    ericg LawnSite Silver Member
    Posts: 2,550

    There is a valve stem seal only the intake valve on these engines.
    I agree with PistonSlapper that you should perform a compression and or leakdown test.
    The results of those tests will tell the true story.
     
  9. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Valve seals will not give you these problems on a Command twin...
    The drain in the head would have to be clogged to get the oil level high enough in the valve cover to drain thru the valve guides..
    A broken reed valve is always a possibility on smoking issues...but not on startup..
    A headgasket leaking at the oil drainback hole could leak a small amount of oil into the cylinder when it is not running....probably the case...
     
  10. Monroe74

    Monroe74 LawnSite Senior Member
    Posts: 322

    Not saying your wrong. It's what fixed my 27hp Kohler command.
     

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