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Help 2 cycle mower blows gas from muffler

Discussion in 'Mechanic and Repair' started by schnurmac, Apr 7, 2008.

  1. schnurmac

    schnurmac LawnSite Member
    Messages: 4

    I have a lawnboy mode 10323 commercial 2 cycle mower. Its on its third year. I am a home owner. Its only used in the spring and summer. It blows gas and oil from the muffler when running. It also will leak out when not in use in my garage. Is this a relly bad sign or? would it worth taking and have serviced.:help::help: I bought from lowes new last 2 cycle they were selling display.
  2. Jay Ray

    Jay Ray LawnSite Fanatic
    Messages: 6,510

    Your easiest possible fix is a simple, plastic fuel shutoff valve, about $5. The kind that has the 90 degree angle works easiest I think. LB is famous for fuel getting past the carb while sitting. Sometimes builds up liquid in the muffler while the LB sits in the garage. When you finish mowing just turn off the fuel shutoff valve and let it run until it quits by itself. Open the valve next time you use the mower. You can put a repair kit in the carb but it will happen again soon enough.
  3. schnurmac

    schnurmac LawnSite Member
    Messages: 4

    Thanks. Yea after I start it up it blows it out and I wait for it stop blowing gas out then I mow and its fine. Makes sense. I didn't know if it was a sign of failure. I have never done any maintenance on it. Is there anything I should do to it as in routine maintenance? I do clean the air filter twice a year and that's it. The manual says to take the plate off that's under the deck and clean any deposit that has formed with a wooden dowel also the inside of the muffler. I would but it then says use silicone to seal it back on. Why don't they make a gasket for it? I just don't like waiting for things to dry.
  4. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    The most significant problem with the LB carbs is the cork float. Over time' along with storing them over the non cutting season with fuel in the carb bowl the float swells. This condition allows the float to contact the carb body before the needle is allowed to fully engage the seat, thereby permitting gas seepage into the muffler. In my opinion this problem has been hastened by the ethanol in fuel. I have no idea what type of product the vendor uses in the manufacturing process to coat the cork but it is not impervious to current day fuels. I have found fuel soaked floats as much as 1/8" thicker than new ones when placed side by side. A shut off valve as previously suggested is a good solution. I have never understood why LB refused to move to a plastic float similar what is commonly used on Briggs. Some of the older LB's that used the Walbro carb with the plastic float were never a problem.

  5. peak2p2000

    peak2p2000 LawnSite Member
    Messages: 15

    take it in to the shop the float in the carb is the problem and thats not a major deal.

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