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Discussion in 'Mechanic and Repair' started by netman, Apr 24, 2002.

  1. netman

    netman LawnSite Member
    Messages: 1

    I have a question on chainsaw motors. After setting with no fuel all winter, both of my chainsaws will not run. they both start and run for bout 30 seconds and then stop as if starving for gas. I have cleared the fuel lines and am lost beyond that. I forgot to mention that one of the saws is an Echo and the other is a Husvarna. Thanks:blob4:
  2. Check the vent on the gas caps
    Easy way to see if this is the problem start the saw and before it quits loosen the fuel cap and see if it continues to run. If this is the problem you will probably notice pressure build up in the fuel tank.
  3. Molerj

    Molerj LawnSite Member
    from Ohio
    Messages: 40

    Sounds more like a carburetor problem. I believe
    the gas cap theory would take longer than 30 seconds before it quit but you can still try it. You may want to check the fuel filter in the tank. Then move to the carburetor. Take off the air cleaner & try to dribble fuel thru the carb. with the saw running. If that will keep it running then you will have to take apart the carb. Cleaning may help (use spray carb. cleaner & a tag wire thru all the tiny holes) or you may need to replace the diaphragm. You might as well get a carb. kit. Don't try to use all the parts as there will be some extras in there. I'm assuming you checked out the plug already. Hope this helps or at least gets
    you going in the right direction.
  4. metrognome

    metrognome LawnSite Member
    Messages: 3

    FYI--Pressure build up in the fuel tank of a chain-saw is a normal condition caused by the fuel expanding from the heat generated while running. The tank vent valve is usually a "duck-bill" type that's either located in the gas cap or in the side of the tank. It's purp[ose is to allow air to enter the tank as the fuel pump (which is integral with carb) sucks fuel out. If this valve get's gummed shut then there would be sufficient air in the tank to allow the engine to run for ten or twenty seconds before it "leaned out" from lack of fuel cause you can't suck out of a vacuum.
    Sounds more like there's a gum or varnish yuck closing off one of the fuel jets or nozzles or even a gummed up or just plain dirty fuel pickup filter.
  5. Remo Sid

    Remo Sid LawnSite Member
    from USA
    Messages: 55

    Sounds like the diaphrams in the carbs are dried out, and not pumping enough fuel. Replace and clean carb.Small Engine Repair help

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