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Grasshopper 718K runs rough...

Discussion in 'Mechanic and Repair' started by JCC, Aug 9, 2007.

  1. JCC

    JCC LawnSite Member
    Posts: 1

    Hey guys! I've got a 10-year-old Grasshopper 718K that has recently developed a problem. After mowing 30 minutes, or so, the engine begins to stutter and occasionally backfire. I suspected water in fuel, but here's the head-scratcher...When I turn off the PTO, the engine runs perfect. If it was a fuel problem, wouldn't the engine still stutter when the PTO is dis-engaged?

    Now, I'm wondering if the problem isn't electrical...

    Any thoughts from the Gurus?

    Thanks in advance for any replies. :)
  2. thecrankshaft

    thecrankshaft LawnSite Member
    Posts: 172

    Check for spark on both sides when the engine is hot.
  3. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Posts: 921

    "f it was a fuel problem, wouldn't the engine still stutter when the PTO is dis-engaged?"
    Not necessarily. If you had a partially restricted fuel filter, it could eventually starve out under load conditions (when the engine requires more fuel), but run fine in an unloaded state.
    Also, when an engine is under load, the governor opens the throttle plate on the carb, allowing more air into the engine. This effectively raises the compression ratio. A marginal ignition system (plugs, coil, etc.) may fail to fire the spark plug under the higher compression.
    Have you done a few of the relatively inexpensive "basic" maintenance procedures such as new spark plugs & fuel filter?

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