Bad Gas?

Discussion in 'Lawn Mowing' started by heybruck34, Dec 31, 2003.

  1. heybruck34

    heybruck34 LawnSite Senior Member
    Posts: 300

    I have a John Deere GS30 walk-behind that I rebuilt. I put a brand new engine- Kohler 15 on it in April. It runs great once I get it running.

    The problem is after it sits for a while (couple days or so) it will start fine but then start sputtering and die. It runs a little better on choke but eventually will die. At first I was able to get it running again.

    After happening a couple times, I took the fuel line off BEFORE I started it. I just let the fuel drain on my driveway and it looked like tea for about 2-3 seconds and then was like normal gas. Hooked up the line and it ran FINE for hours.

    Everytime I want to use this machine- I have to repeat this process: take line off- let it drain until it is clear gas, hook up and start. IF I don't the engine runs for a couple seconds until (I'm guessing) the fuel in the carb is used up and then it dies. WHY?

    The fuel line was new in April AND I put a new fuel pick-up in it. This is a siphon system- not gavity feed.

    Any ideas? New fuel line?
     
  2. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    Drain the tank. Add some fuel stabilizer and put in some fresh gas. See how it does from there.
     
  3. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    It may be the gas but I doubt it. Change it like Envy said and try again. You don't mention a fuel filter. If the filter is old replace it. If it doesn't have a fuel filter then add one. Remove the bowl from the carb and check for dirt or water. The fact that the mower starts and then stops, you play with the fuel lines and then it runs great leads me to believe there is dirt or water in the carb. Have you tested the fuel pump? If it's not a gavity feed then it must have a fuel pump. There are no "siphon" feed carbs in Kohler's 15 hp verticle engines.
     
  4. hoyboy

    hoyboy LawnSite Senior Member
    from Chicago
    Posts: 346

  5. bpdmower

    bpdmower LawnSite Member
    Posts: 9

    I had the same prob. with my scag cub, it had water in the carb bowl.

    By the way, this is a great site. Lots of information.
     
  6. sbvfd592

    sbvfd592 LawnSite Senior Member
    Posts: 668

    Try it. If it dosent work well contact your dealer and say hey this is my prob do you have any sugestions?
     
  7. rshofcols

    rshofcols LawnSite Member
    from ohio
    Posts: 86

    sounds like you got a couple of good hints to go with,try the fuel filter,dump the gas and if that dont work -you may have carbon buildup in the carb or water somewhere in the system.Gasoline in mowers only lasts 30 days before it starts breaking down and the alcohol turns to shellaq or varnish inside the guts of the mower(bearings,seals,rings etc)put stabil in when you get it fixed and it will last till spring-good luck done this 4 times with hondas and deeres
     
  8. dishboy

    dishboy LawnSite Platinum Member
    from zone 6
    Posts: 4,307

    Running with choke but not without choke tells me that it most likely running lean. Gas looking like tea, your filter is most likey not filtering any more. If your filter is plugged or partially plugged this will create a lean run condition also. If you ran the "tea" into the carb you have the heavy sediments floating around in the bottom of the bowl that will plug gas circuits creating lean run situation.
    If it were me I would remove all gas, rinse tank and replace with fresh gas. I would replace filter with a automotive type canaster filer[NAPA] Does the gas run clean now?. If so I would run engine. If it runs good now you might have fixed the problem, understanding that if there is "stuff" floating around in the carb bowel it will probably make it's way back into the gas circuits in which case you will have to pull the carb apart, spray all circuits with carb cleaner and blow out with compressed air. This should fix your problems, but it could be something else entirely I would start here first. Tom
     
  9. PLI1

    PLI1 LawnSite Senior Member
    Posts: 254

    1. Drain gas and clean gas tank
    2. Replace fuel filter, making sure it faces the right way!
    3. Remove carbureter, disassemble and clean thorougly.
    4. Reassemble and replace carburetor.
    5. Refill with fresh gasoline and add fuel stabilzer "since the unit
    will probably sit for the winter"
    6. While you are at it, check and replace spark plug if necessary.

    It sounds as if the fuel supply may have gotten contaminated or gum and varnish may have developed. It doesn't take long for some fuels to go bad, especially if it was sitting in a 3/4 empty fuel can or gas tank.
     
  10. heybruck34

    heybruck34 LawnSite Senior Member
    Posts: 300

    thanks for the responses. Here's some more info. Once I remove the fuel line and drain the "tea colored gas" until I see normal gas- the mower will run fine for hours. I can shut it off and start it again no problem at ALL throttle ranges.

    The main time I see this problem is if the mower has been sitting for a while- days or weeks. I am going to replace the fuel line and the filter, hopefully this weekend. It's like the gas in the fuel line goes bad?

    I'll let ya'll know if that does it. Next thing I'll do is some of your other suggestions- clean the carb and rinse the gas tank. Fun stuff huh?

    Thanks everyone.
     

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