Stihl 4mix fs100rx problem?

Discussion in 'Lawn Mowing' started by HenryB, Jul 21, 2007.

  1. HenryB

    HenryB LawnSite Bronze Member
    Posts: 1,829

    My worker says it will just cut off at full throttle sometimes. I ran it and could not get it to do this. However, I noticed it was surging (hunting) at idle. Any suggestions?
     
  2. carcrz

    carcrz LawnSite Silver Member
    Posts: 2,085

    Mine has also just started doing that. It takes a minute to warm up & then if it turn it on its side to edge, it will cut out one me until I turn it upright again.
     
  3. anj

    anj LawnSite Member
    Posts: 167

    I Had The Same Problem With My Fs100rx. They Replaced The Tank Valve. That Solved That Problem But Now The Sucker Runs Ruff As Heck. Just Vibrates Like Crazy When I Use It. I Put A New Head On It And It Still Does The Same Thing. My Other 100rx Runs Fine But This One Has Always Been A Problem. Anyone Have Any Ideas?
     
  4. MuleCutter

    MuleCutter LawnSite Member
    Posts: 212

    my idea is to get away from the 4-mix trimmers. after a month of owning my FS100rx the power decreased DRAMATICALLY and had to ditch it cuz of valve problems. i ended up getting a credit on it and with that money back i decided to try an echo 261T. had it 2 weeks and so far i love it other than how hot the clutch drum gets on my arm. i also put a stihl head on it cuz the echo head feels too sensitive. it throws string at the slightest bump.
     
  5. fiveoboy01

    fiveoboy01 LawnSite Silver Member
    Posts: 2,988

    After having my FS90R for around 2 months now, I concur with that statement.
     
  6. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,329

    I don't think the clutch drum gives off heat it should not slip unless you are not running full open....but the units do run hot and there is an add-on heat deflector they came out with.....for sensitive feed just stretch the spring if you want less feed out...
     
  7. HenryB

    HenryB LawnSite Bronze Member
    Posts: 1,829

    Update: Adjusted the valves today (1st tim, Cleaned air filter, new plug and de-carbanized exhaust port; It runs like new again. I really like this trimmer! :clapping:
     
  8. john_incircuit

    john_incircuit LawnSite Senior Member
    from NC
    Posts: 309

    How do you de-carbonize the exhaust port on the Stihl?
     
  9. Lawnworks

    Lawnworks LawnSite Fanatic
    from usa
    Posts: 5,407

    I love 4mix trimmers... they have been the only trimmer that has lasted longer than a year for my company. I have about 10 of them and some are going on three years. I would get one season out of redmax trimmers.
     
  10. sawman65

    sawman65 LawnSite Senior Member
    Posts: 751


    stihl offers a solvent for this and it needs to be done as regular maintance.
    the build up of carbon will not let the valve's close this = loss of power.the valves need to be adjusted after a few tanks of fuel are run.it can be done as warranty. if you use cheap mix all these problems will happen.use stihl oil and you will have less of these problems
     

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