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Kohler CH20S Troubles

Discussion in 'Mechanic and Repair' started by jriltex, Apr 21, 2007.

  1. jriltex

    jriltex LawnSite Member
    Messages: 4

    Have a Kohler CH20S in a Kubota ZTR and experiencing some difficulties. Ran fine for 40 hours or so, then began experiencing unexpected oil consumption issues along with the drivers side spark plug getting severely fouled after several hours of mowing. Clean the plug and it runs OK again. Took to the shop and they did compression test and indicated compression OK. Replaced plugs, oil, oil filters and returned. Ran for several hours and experienced the same problem again. Returned to the dealer and they ran a leak down test and determined there was a problem. They are saying the cylinder and rings are damaged. They are saying the engine got "dusted" due to air filter issues resulting in this problem. My question is how do I know if this is correct diagnosis or if there could be a mechanical event such as a blown head gasket or something else unrelated to user cause? Obviously there is a matter of warranty qualification being discussed. If it is my fault, then I will own up to it, however I would like to know how to determine since there has been no diagnosis beyond the leakdown test and the service department saying the above. Thanks...

    I MOW ALONE LawnSite Bronze Member
    Messages: 1,961

    how can they say the cylinder and rings are damaged but the compression is good. does'nt make any sense. what was the compression reading on each cylinder. i would bet there full of s**t and that you have a blown head gasket.
  3. jriltex

    jriltex LawnSite Member
    Messages: 4

    They did not provide the info to me yet. I am actually picking the unit up tomorrow and plan to check the compression myself before I go down the path of a replacement motor. Funny thing is when I clean the plug and blow the cylinder out with a few cranks of the engine prior to replacing the plug it will run effortless for an hour or two as long as I stay in mid power range. I would assume if the rings were shot I should also see significant blue oil smoke in the exhaust, which I am not. But I defnitely am having to add half a quart of oil for a hour or so fo mowing. Thanks for the quick reply.

    I MOW ALONE LawnSite Bronze Member
    Messages: 1,961

    half a quart of oil in an hour and it is not burning it out the exhaust thats strange. still bet it's a head gasket.
  5. jriltex

    jriltex LawnSite Member
    Messages: 4

    Yeah, it confused me too. It does have some normal smoke but at half quart an hour I would think I would be mistaken for the skeeter spraying trucks from the 60's. Maybe I am just not noticing it. Any tricks for isolating to a head gasket...short of R+R head and checking it on teardown? I really appreciate the help. Thanks

    I MOW ALONE LawnSite Bronze Member
    Messages: 1,961

    what do you mean normal smoke do you mean a little on start up or a little constantly when running. i had the same problem your having with 150 hours on my 27hp kohler but mine was blowing a decent amount of smoke clearly visible. compression was good i took to dealer they told me they did'nt think it was head gasket or reed valve and they thought it was probably rings. they would'nt know until they tore it down. i said bulls**t not with 135 psi in each cylinder. brought it home took the head off and sure enough head gasket was blown $10 and a couple hours later problem fixed. and they said i probably needed to buy a new shortblock. go figure
  7. jriltex

    jriltex LawnSite Member
    Messages: 4

    Thanks...I will give it a go and see if mine is blown...after all what do I have to lose? ;-) Worse case I replace it.
  8. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 963

    Before you change the gasket, I'd check for spark on that cylinder when the problem occurs.
    My guess is head gasket too though.
  9. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    What air filter issues are they saying took place ? If that was the case both cylinders would likely be doing the same thing.

    Take the unit to another shop !!! I'll put money on a blown gasket.

    I just don't get how some shops know better and try to rip customers off.
  10. pugs

    pugs LawnSite Gold Member
    Messages: 3,025

    Just a FYI. An engine can have good compression, but may show problems in a leakdown test.

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