Discussion in 'Mechanic and Repair' started by lawn&orderinc, Feb 24, 2008.

  1. lawn&orderinc

    lawn&orderinc LawnSite Member
    Posts: 31

    anyone ever had problems with clutches going bad on fs85 weedeaters or fc75 edgers? if so is it hard to replace?
  2. Roger

    Roger LawnSite Fanatic
    Posts: 5,923

    What is the problem with the clutch? One problem that happened to my FS85, and has been experienced by another(s) that have posted, is a broken spring. Three springs are used to pull in the flying dogs that engage when the engine speed reaches some specific rpms. This problem is manifested by the clutch not fully disengaging when the engine speed is low. Replacing the spring is an easy task -- if you are doing so, I suggest replacing all three at the same time.
  3. lawn&orderinc

    lawn&orderinc LawnSite Member
    Posts: 31

    the head is always turning making it hard to start. stalls at low rpms. i love stihl but i've had this happen on 2 weedeaters and 1 edger. thanks for your input.
  4. Roger

    Roger LawnSite Fanatic
    Posts: 5,923

    That sounds like the clutch is not disengaging, and follows the pattern I described above.

    To my regret, when I made my repair, I did not shoot any pics of the procedure. Therefore, I have nothing to show you.

    My suggestion for what it is worth: Go to your dealer and ask for new clutch springs. Perhaps your edger is an FC85. FC85 and FS85 share the same clutch models. If you do some of your own repairs, the procedure is quite easy, and takes only a few minutes. The power head needs to be take off from the handle/tube. Making that separation will expose the clutch. I would be surprised if you don't find one of the three springs broken. Removing the old one and putting on a new one only requires a pliers or ViceGrips. I don't remember what I used, but I do remember that getting the new spring mounted was simple. As I said earlier, since you have it open, I would suggest replacing all three springs. Undoubtedly the failure is due to fatigue. If one of them fails, the others could be not far behind.

    Like I said, that is MY suggestion. Perhaps somebody else has something else to share as a possible cause and remedy.
  5. sawman65

    sawman65 LawnSite Senior Member
    Posts: 751

    one question ...... is the grass guard still in place or have you took it off to run longer line?
  6. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

    In 6 years I've never had a clutch give out, I don't run guards.

    You need to buy a tube of Stihl grease that's made for gearboxes, cost around $8.
    Then pull off that bolt on the side of the gear box (on the head itself), thread the Stihl grease tube in there and squeeze!
    Once you can't squeeze no more in there, unthread the grease tube and re-cap for another use, and re-install the bolt.

    It's got a bolt that closes up the filler hole, the Stihl grease tube threads perfectly in there, made for that.
    Afaik you can use the Stihl tool but I believe you have to use the torx end for this bolt, thou a hex wrench would work also.

    This should be done once a year, hedge trimmers and certain attachments and other stuff, too, grease up the gear boxes.
    I think chainsaws are exempt.
  7. jkason

    jkason LawnSite Senior Member
    Posts: 548

    If you don't run guards, you violated warranty. The dealer has no responsibility to fix it. (It's abuse.)

    The reason it's abuse is that when you take off the guard, you also take of the string-cutting knife.

    If that string gets too long, it takes more power to spin a longer string. Power that the clutch might not have been designed for. Also creates a hell of a lot of vibration. Vibration is bad for the machine, and for you.

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