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Kohler engine excess gas in Carburator

Discussion in 'Mechanic and Repair' started by JPL, Jun 3, 2008.

  1. JPL

    JPL LawnSite Member
    Messages: 30

    I've got a 15 hp Kohler that powers my Scag mower.
    When I clean the air filter (everyday) I have noticed that there is a puddle of gas sitting below the air filter. When I start the engine there is a burst of smoke that comes out of the exhaust. After the engine starts the gas is gone. This seams to happen when the mower is stored over night. When I first start the mower it is hard starting most likey from the excess gas.
    Any ideas if it is a problem or what can I do to fix it.
  2. Redneckn

    Redneckn LawnSite Senior Member
    Messages: 294

    It could possibly be how you shut the machine down. I've seen a few times where if you shut it down at full throttle it will pool in the filter base area.

    Are you getting any gas into the sump? If so there is a carb issue for sure. If nothing else you may consider a manual fuel shutoff device.
  3. Lawn-Sharks

    Lawn-Sharks LawnSite Senior Member
    Messages: 912

    I had the same problem but i would get it because it would get hot in my enclosed trailer and heat up the fuel tanks and push gas into the carb, i had to clean the vent holes in the gas caps.
  4. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,283

    I don't know that sounds like a leaky valve.....you can put in a new kit and hope that corrects it, I had to change out the carb on two this year apparently the seat was damaged and can't be replaced. You can put you a gas cutoff and close it on shutdown. Kinda pain but if it is a needle it will keep getting worse and someday you will have it in cylinder and when you try to start it will not pull over.
  5. themow

    themow LawnSite Member
    Messages: 41

    Yea hes right sounds like a seat that may be cracked. I also could be pressure inthe fuel tank. Try storing it one night with the gas cap loosened.
  6. JPL

    JPL LawnSite Member
    Messages: 30

    Thanks Guys, I will check out all those posibilites. There is a a manul shut off under the tank I may have to use it for now. I will try the easy stuff first like cracking the gas cap. If I can get through the season it will be a big help and I can replace or rebuild the carb. this winter. The machine works everyday and when it comes to nights and Sunday I don't have the time as I need to see the wife once in a while that's she tells me.
  7. mowermankevin

    mowermankevin LawnSite Senior Member
    Messages: 270

    JBL, first off, way to go on cleaning the air filters daily, that's so important. The fuel puddling is due to gravity,(tank above carb) and shock. When transported (without a manual fuel cut-off the hydro-shock from the fuel to the carb) can overpower the needle/float in the carb. Toro had stickers on all the mid-size walkbehinds that read, "Before Transporting Turn Off Fuel", I guess the decals cost too much, so what happens is the guys get to the next job, pull the rope, it starts and smokes, they just go on mowing till the mower engine locks up due to oil/gas dilution. I can't tell you the number of engines that came in here locked-up, pull the dipstick and the oil runs off like water. Even the fuel cut-offs leak a little but there a lot cheaper than new engines.
  8. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,283

    You can put a good cut-off in the gas line where it is convenient to get to the ones under tank are usually a pain. And it is possible to get ones that shut the gas completely off.
  9. mowermankevin

    mowermankevin LawnSite Senior Member
    Messages: 270

    Just an update, had a 72 hour Lesco twin hydro come in today, and guess what, even tho the fuel tank in big letters says,"CLOSE FUEL VALVE WHEN MACHINE NOT IN USE IF VALVE IS LEFT OPEN, SEVERE ENGINE DAMAGE OR HARD STARTING MAY RESULT FROM FLOODING (notice still no mention of fuel/oil dilution which can result in a locked up engine, just thought you might like to see how often it happens, keep us posted C'ya
  10. JPL

    JPL LawnSite Member
    Messages: 30

    Sorry I have not done any investigations I have been away and it’s been raining here in Mass. My guys have not been working but as soon as I can dig into it I will let you know. First thing I will have them check the oil before they go out.

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