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stihl 4mix

Discussion in 'Lawn Mowing' started by lawnshark2420, Oct 2, 2007.

  1. lawnshark2420

    lawnshark2420 LawnSite Member
    Messages: 37

    Can someone please tell me what the difference is between the stihl 4mix and the regular?
  2. cgaengineer

    cgaengineer LawnSite Fanatic
    Messages: 15,777

    The 4mix is a 4 stroke that uses mixed oil and fuel to lubricate engine parts. Unlike a 2 stroke that also uses oil mixed with gas, the 4 stroke normally has an oil sump. With an oil sump you cannot turn engine upside down so 4 mix idea came into play. The 4 mix engine is no different in operation then the engine of your car or lawn mower provided they are 4 cycle.
  3. tamadrummer

    tamadrummer LawnSite Bronze Member
    Messages: 1,102

    I believe these are also set up to meet California emmisions standards unlike many 2 cycle products.

    google the term and it will take you directly to the stihl page about 4 mix.
  4. lawnman_scott

    lawnman_scott LawnSite Fanatic
    Messages: 7,547

    the 4 mix have alot more pwer and are much quieter.
  5. lawnshark2420

    lawnshark2420 LawnSite Member
    Messages: 37

    I really appreciate the info, thanks a bunch. I have a fc100 4mix edger and i love it. lots of power,low noise.
  6. TxLawn

    TxLawn LawnSite Member
    Messages: 36

    Just bought a FS100RX and love it. Time to buy another one

    ECHO4LIFE LawnSite Member
    Messages: 21

    When you say 4-Mix run cleaner what are you referring to?
  8. cgaengineer

    cgaengineer LawnSite Fanatic
    Messages: 15,777

    They run cleaner because buy design a 4 stroke is more efficient because a 4 stroke burns all of the fuel mixture intead of losing some of the mixture in the exhaust. It burns about half the amount of fuel (Engine sizes being the same) and has less emissions because the engine fires once every 720 degrees, and a 2 stroke fires once every crankshaft rotation (360 degrees).

    4 cycle engines generally have to be larger displacement to equal the power of a 2 cycle.
  9. Daner

    Daner LawnSite Bronze Member
    Messages: 1,307

    They are more user freindly as well
  10. txgrassguy

    txgrassguy LawnSite Gold Member
    Messages: 3,083

    Basically the 4-mix is a two cycle, four stroke motor that has valves instead of reeds.
    What this means is the valve, exhaust set up allows for a much less quiet operation, which apparently you have noticed and the engine configuration means a broader torque curve as the torque of the engine design offsets the higher rpm of the reed design.
    Regarding the "cleaner" exhaust emissions, the 4-mix powered equipment comes with a catalytic converter to make it CARB compliant - hence the "cleaner" moniker.
    A point for thought, I much prefer the 4-mix motor set-up, I must as I own over thirteen pieces of 4-mix powered hand equipment and have more planned soon.

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