Stihl fs55r trimmer 07 model crapped out

Discussion in 'Mechanic and Repair' started by cannondale23, Aug 28, 2010.

  1. cannondale23

    cannondale23 LawnSite Member
    Posts: 37

    could someone help me out, the symptoms are that the trimmer will bog down and lose power when I press the throttle to give it more rpm. it does smoke sometimes... if you have this model any quick solution that you implemented, hopefully someone can post some helpful hints.

    thank you
  2. cannondale23

    cannondale23 LawnSite Member
    Posts: 37

    update... I put in a new carb, similar problem... the trimmer loses power and dies when held on an angle(i guess it runs ok until it's on its side), I took off the exhaust and it ran better but as soon as a turn it on the side it dies, I noticed the exhaust is full of gas... any ideas.. thanks
  3. cannondale23

    cannondale23 LawnSite Member
    Posts: 37

    second update, I ran it without the exhaust a few times and it seems to be doing better, even held on an angle, I think having the trimmer in the truck resting in different positions caused the exhaust over time to end up with gas. I'll post a final solution once I purchase a new muffler for the unit.
  4. cannondale23

    cannondale23 LawnSite Member
    Posts: 37

    third update, purchased a new muffler and a new carburetor and the problem went away...tried it out today with 1.05 line and the thing worked like a champ...
  5. dboyd351

    dboyd351 LawnSite Bronze Member
    Posts: 1,101

    If you still have the old muffler, take a look at the spark arrestor screen. My guess is that screen is plugged up with carbon. That's why replacing the carb did nothing, but when you replaced the muffler it ran well again.
    Next time, if the screen is clogged with carbon, you can take it out, burn the carbon off with a torch, wire brush the screen clean and re-install it. Same results, for free!
  6. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

    As a general note if the spark arresting screen is carbon clogged
    it means you are most likely using the wrong fuel mixture.
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,245

    Not necessarily,,,If you take off the guard and use you trimmer for a 22in mower,you can carbon up the cylinder exhaust port and the muffler..

    Are you posting in your sleep ? seems all your posts are after midnight....

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