Stihl FS55 Trimmer help

Discussion in 'Lawn Mowing' started by Buck_24, Oct 18, 2008.

  1. Buck_24

    Buck_24 LawnSite Member
    from Midwest
    Posts: 3

    I have a 4 year old FS55 trimmer. Early this summer, it started running rough, when I give it some gas, the engine dies.

    I finally took it into the dealer and they are telling me it needs a new carb. Can this be true?
     
  2. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    That's my thought. There is really very little that can go wrong with these simple 2 stroke engines. If the coil, plug, filters and compression are good then more than likely it needs a carb. Is it hard to start? How is the primer bulb? A lot of people might say it has a gas cap vent problem but that doesn't account for it running rough.
     
  3. Buck_24

    Buck_24 LawnSite Member
    from Midwest
    Posts: 3

    Once it starts, it's pretty decent, just if I give it full throttle, the engine dies. A friend said to check the muffler screen. Any idea?

    Also, I use 89 octane, should I be using something higher, like premium gas?
     
  4. Wittapp

    Wittapp LawnSite Member
    Posts: 195

    I had a similar problem with my fs85 this season. I changed all the filters, new fuel line, new plug and sprayed cleaner in the carb. It still ran a little rough, but was getting better, so, I cleaned the carb 2 more times. That seemed to do the trick. Good luck with it. Also, does it need a new carb, or does that one just need a rebuild kit?
    Dave in Dayton
     
  5. Buck_24

    Buck_24 LawnSite Member
    from Midwest
    Posts: 3

    Can I get something I can mix with my gas to clean the carb?
     
  6. Wittapp

    Wittapp LawnSite Member
    Posts: 195

    I use the spray cleaner. And definately check the muffler screen and the air and fuel filters. If you want, you can PM me and we can exchange numbers or e-mail if you want more help.
     

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