Well it finaly happened. Got a kohler thats giving us a problem.

Discussion in 'Mechanic and Repair' started by ProStreetCamaro, Jun 11, 2008.

  1. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Messages: 4,287

    Our new 160Z we got this spring has the 25hp kohler. The engine runs very strong but its now smoking like a freight train every time its started. It smokes non stop at idle and at full throttle it smokes for about a minute then clears up. Its still burning oil at full throttle because you can smell it but you cant see it.

    I did a compression check and both cylinders are right at 170 pounds. The left plug is oil saturated (its on the left of the carb when your looking at the carb from behind the machine). The right plug looks normal.

    Anybody have any ideas? I am thinking it could be.

    1. Blown head gasket
    2. torn or broken intake valve seal
    3. cracked ring
    4. sticking reed valve

    With the compression normal in my mind that throws out the head gasket. It didnt smoke when new. Started a little at around 30 hours and has gotten worse and worse to the point i am about to throw on a new blade clutch on our old lazer back up machine and take that to work today.
  2. M&M Mowing

    M&M Mowing LawnSite Member
    Messages: 113

    Ive seen broken rocker arms on the kohlers but you would definately hear that.
  3. jkason

    jkason LawnSite Senior Member
    Messages: 546

    Could be any of those problems.
    What do you consider normal compression? Anything over 60 psi will run.
    Head gasket will "whistle" untill it heats up, then stop.
    Intake vale seal will turn the stem of the valve black.
    A cracked ring will break, causing a really bad day.
    Sticking reed valve (on the breather, I assume) will cause a lot of smoke, then might unstick itself when the engine gets up to temp.
  4. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    Sounds like you will need to do a leak-down test.
  5. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Messages: 4,287


    When you pull the breather that leads to the carb out of the valve cover it is blowing blue smoke out pretty heavy. I have a sneaking feeling it has a blown head gasket. I took a short video of whats going on I will post up in a bit when I get home.
  6. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Messages: 4,287

    Yeah I dont have that tool but your right that would be helpful. I think we are going to take it on in to the shop tomorrow and have them see whats going on. I wish I could work on it myself with out voiding the warranty. I have no faith in the shop we purchased it at.
  7. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Messages: 4,287

    Alrighty here is the video. Make sure to watch the whole thing. It doesnt smoke to bad at first.

    Click to watch

  8. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    I seen the video. With that much coming out of the breather I say it looks like you have a lot of exhaust blow by. Do a leak down test. It looks like a lot of exhaust is getting back into the crankcase.
  9. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    I hate to come off sounding stupid but did you check the oil level to make sure it didn't somehow get over filled?

    Once that's done, seeing how you're getting crap from that valve cover hose, an easy check is to just pull the valve cover(s) and take a look see...
  10. ProStreetCamaro

    ProStreetCamaro LawnSite Platinum Member
    Messages: 4,287

    Yeah it really has me thinking it could be a head gasket or broken rings. If the head gasket isnt sealing or is blown between the pushrods that could be allowing the oil to get into the cylinder and when it compresses and ignights its allowing some exhust gas to come back through into the head filling the crank case.
    We are going to take it in to the dealer today I think.

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