Stihl 4 mix problems

Discussion in 'Mechanic and Repair' started by A Leaf Above, Aug 1, 2010.

  1. cgaengineer

    cgaengineer LawnSite Fanatic
    Messages: 15,778

    I agree, its only 10% people.
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  2. derekarbeiter

    derekarbeiter LawnSite Member
    Messages: 233

    Ive had the same problem with my two FS 90Rs. I have a 2007 and a 2009 model and love the power and fuel efficiency of both but the 2009 doesnt have hardly any use to it and its already starting to act like my 2007 model, it wont idle without dying, I finally had to adjust the old one to give it some more juice I may try the same with the other. Today my old one just started reving up on my without me even touching the throttle. I recently bought a third trimmer but decided to go with Echo and I have to say although this trimmer is a two cycle and has smaller displacement than the Stihls, I'm very impressed. I guess I will try to do my best to fix the problem if anyone on here has any solutions. I love Stihl products and the company is great to deal with. Dont even get me started with Stihl gas caps though! POS!!!!
  3. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,588

    Got to stay on top of adjusting the valves on these 4 4-mix was at .012" after 4 mos. use on exhaust. Needs to be about .003"
  4. genesis215

    genesis215 LawnSite Senior Member
    Messages: 795

    I would try replacing the tank vent. They seem to be an epidemic lately on the Stihl's. Also try the spark plug. If all fails then adjust the carburetor.
  5. cgaengineer

    cgaengineer LawnSite Fanatic
    Messages: 15,778

    Try adjusting valves first if you haven't done it yet.
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  6. Dave Archer

    Dave Archer LawnSite Member
    Messages: 27

    If you don't want to get bit by crocodiles, stay out of the water they inhabit...I owned Stihl in the past and the ONLY piece of equipment I owned that was made by Stihl that didn't give any problems was the 2 stroke, 2 stroke, 2 stroke, 2 stroke, 2 stroke, 2 stroke, 2 stroke, blower. What kind of blower? 2 stroke. What Stihl equipment did I have problems with? Not the 2 stoke. BAM! Don't want to adjust valves? 2 stroke. Don't want the issues of the 4 mix? 2 stroke. Want a good fix? You guessed it...Don't buy 4 mix!
  7. cgaengineer

    cgaengineer LawnSite Fanatic
    Messages: 15,778

    Been using 4 mix for 5 problems. I've had more starting problems from 2 strokes.
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  8. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,337

    Me too...
    I think the biggest problem with the 4mix engines is ignorance...
    Mechanics have always been able to turn a screw...change a sparkplug or a fuel fix a 2 stroke trimmer....They have become complacent and are intimidated by the new technology...I've seen more than 1 guy ...that calls himself a tech...look with fear when laying it on the counter for repair...

    The best advice I can give a mechanic is to get a broken 4mix engine..and do a complete teardown...every nut ..bolt..and bearing...once you get familiar with all the should remove some of the mystery with them...
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  9. Dave Archer

    Dave Archer LawnSite Member
    Messages: 27

    some people don't have the luxury of being able to sit in the garage all day working on 4-mix engines in order to "figure them out", anymore than we have time to figure out the universe. You buy an FS110R for almost 400 dollars, you would think you wouldn't have to know why the atoms of the machine make it the issue it is...Most people don't have a wrench to fit the atoms on the 4-mix, or the time to turn every atom to get those machines working properly. I have yet to have one starting issue with any of my 2 strokes, or the 2 stroke Stihl blower I used to own.
  10. Roger

    Roger LawnSite Fanatic
    Messages: 5,943

    A wrench comes with the machine.

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