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lawnboy starts then stalls

Discussion in 'Mechanic and Repair' started by Bunton Guy, Apr 30, 2008.

  1. Bunton Guy

    Bunton Guy LawnSite Bronze Member
    Messages: 1,917

    I have a lawn boy self propelled bagger mower with a Tecumseh engine on it. Think its 6hp but not completly sure.

    It will start just fine run for around 2-3 minutes then shut off with no warning...almost like its starving for fuel. It WONT restart no matter what till the engine cools down some. Usually 10 minutes or so wait time before it starts. Then it will start again and run fine for 2-3 minutes and shut down again.

    It does not have a fuel filter that I can see otherwise that would be my first thing I would check. Whatever is going on its apparently loosing prime of fuel.
    Right as it shuts off it will surge for maybe 2-3 seconds and then stall JUST like when I mower runs out of fuel. Apparently its something in the carb? I have sprayed a can or two of carb cleaner through the carb but never taken the carb off or apart. Where should I start looking?
  2. lawnboy dan

    lawnboy dan LawnSite Gold Member
    Messages: 3,711

    bad ing coil
  3. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    As LB Dan states, it sounds like a defective ignition coil. Put an inline spark checker on it, start and let run the 2-3 minutes you say it takes to die(or until it dies). Watch for a lack of spark as it dies. If it still has spark as it shuts down you more than likely have a fuel related problem--most likely a piece of debris in the carb bowl that is temporarily blocking the main jet. Not saying that it isn't a coil related problem but I haven't experienced many problems with Tecumseh coils. On the other hand, I"d like to have a C note for each Lawn Boy coil that I've replaced.

  4. Bunton Guy

    Bunton Guy LawnSite Bronze Member
    Messages: 1,917

    The only thing that makes me think it is fuel related is that when I desperatly needed to finish a fenced backyard that I promised I ran it with a can of Ether for a few minutes. After the normal 2-3 minutes before it would stall out everytime it would attempt to die I would shoot it with ether every 5-10 seconds until done. Which was only a 20X40 patch of grass. If it was a coil issue it wouldnt put out enough spark,compression or heat to fire over the cold shot of ether.
  5. 0526

    0526 LawnSite Member
    Messages: 10

    Check the fuel cap. Maybe not letting air into tank.
  6. Bunton Guy

    Bunton Guy LawnSite Bronze Member
    Messages: 1,917

    I will have to give this a try. I never checked the fuel cap. Mower has been sitting in the corner of the shop for months now.
  7. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    Replace the inline fuel filter, if it doesn't have one check for an in-tank one.

    Pull the carburetor bowl and watch for little parts you don't lose any, but check
    and make sure all that float thing is in working order and fuel is getting through.

    After that I'm also leaning towards the coil...
    But you could get an ignition spark testing tool to verify this.
  8. jeffex

    jeffex LawnSite Bronze Member
    Messages: 1,933

    my lawn boy silver series won't re-start when it gets hot until the coil cools down. I replaced it once and its back to its old tricks. Cleaning the rust off the coil and the magneto helps. when you start it in the cold weather it needs to be primed several times to keep it running until it warms up some as well. I just bought a inline spark tester this spring and will carry it with me to test when the problem steps up again. I might as well get a new gas cap too...good tip there. This mower is from 2001 and is the best dam 21" mower in the world but it is not without its problems . I scavenged tires from a broken lawnboy and the rear drive unit.
    Last edited: Mar 20, 2009

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