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Stihl 4-mix

Discussion in 'Lawn Mowing' started by McCarty'sLawncare, Jan 7, 2008.

  1. McCarty'sLawncare

    McCarty'sLawncare LawnSite Member
    Posts: 51

    Hey all I recently bought a FS-130 and a BR-600 a couple days ago Im loving these 4 strokes. This is my 1st Stihl experience from being a long term echo operator. I keep hearing mechanics saying run them wide open, at all times. Dont continue to rev and bring it back down to idle. If you do it will mess up the valve and clog it up. Is this true?
  2. fastcat

    fastcat LawnSite Senior Member
    Posts: 799

    there not 4 strokes just 4-mix
  3. ProMo

    ProMo LawnSite Bronze Member
    Posts: 1,468

    actually they are a 4 stroke engine.
  4. fastcat

    fastcat LawnSite Senior Member
    Posts: 799

    4 stroke engines dont require you to pre mix oil and gas. they have a tank for gas and a tank for oil and they mix in the engine.

    i could be wrong but i have 2 4-mix peices of equipment
  5. tyaroch

    tyaroch LawnSite Member
    from MI
    Posts: 119

    The website says it uses 50:1 mix.
  6. fastcat

    fastcat LawnSite Senior Member
    Posts: 799

    yea so if it calls for mix then it is a 2 stroke. 4 strokes dont require a mix
  7. fishmagnet

    fishmagnet LawnSite Member
    from Texas
    Posts: 42

    Stihl 4-Mix engines are four stroke engines that run on two-stroke pre-mixed fuel & oil.

    One could argue they're a 'hybrid' engine, but four strokin' nonetheless!
  8. txgrassguy

    txgrassguy LawnSite Gold Member
    Posts: 3,083

    Fish, I have over fourteen different 4-mix Stihl motors and I have never heard about valve clogging.
    These motors are very sensitive towards a proper oil:gas ratio - if you increase the ratio to 40 or 32:1 that is when clogging occurs.
  9. Two Seasons

    Two Seasons LawnSite Senior Member
    Posts: 791


    You don't know what 4-mix technology is apparently. 4-mix engines use the 2-stroke oil to lubricate the crank and internals on it's way to the intake valve of the 4-stroke engine.

    Stihl designed this engine so that is does not require crankcase oil, so the machine can be used at any angle. Conventional 4-stroke engines, depending on the angle of use, can be starved for oil.
  10. Accu-cut Lawn Care

    Accu-cut Lawn Care LawnSite Bronze Member
    Posts: 1,206

    LOL. You seem so sure of yourself... But you are wrong.

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