no power

Discussion in 'Lawn Mowing' started by GrassmasterB, Aug 16, 2004.

  1. GrassmasterB

    GrassmasterB LawnSite Member
    from Florida
    Messages: 201

    this morning on first yard cranked trimmer (stihl fs 80) idles fine but when i hit the throttle motor bogs and has trouble reaching maximum rpm's. changed spark plug same problem. checked air filter and cleaned element, ran trimmer w/wo air filter with no change. checked filter on pickup, appears to be clean. removed spark arresting screen, no change. gearbox has been greased and gas mix is correct. is there something else i should check? someone told me i need to grease the shaft. could that be the possible problem? if so should i do that or take it back to the dealer because it was bought new in february and its still under warranty? trimmer has approximately 125 hrs.
  2. jbell113

    jbell113 LawnSite Senior Member
    Messages: 654

    Is there a fuel filter?
  3. tiedeman

    tiedeman LawnSite Fanatic
    from earth
    Messages: 8,745

    there is a carbon build up somewhere
  4. allamericanman

    allamericanman LawnSite Member
    Messages: 6

    You need to take the muffler off and clean the exhaust port. It will problably have a lot of build up. Works every time for me.
  5. HOMER

    HOMER LawnSite Gold Member
    Messages: 3,183

    I did all that but I think the thing that really helped it was shooting some carb cleaner in it while it was running.........she's smooth as silk now.
  6. TClawn

    TClawn LawnSite Silver Member
    Messages: 2,036

  7. Shuter

    Shuter LawnSite Bronze Member
    Messages: 1,171

    There is a fuel filter in the tank on a small suction hose.
  8. bj_y

    bj_y LawnSite Member
    Messages: 8

    Will too much carb cleaner do any harm at all, or would it be good if this is done periodically as preventive maintenance?

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