Fuel question

Discussion in 'Lawn Mowing' started by KTNC, Jul 6, 2003.

  1. KTNC

    KTNC LawnSite Member
    Messages: 88

    In your 2 cycle equipment, such as trimmers, what does everyone use for the fuel mixture? 87 or 93 octane? I have a Stihl FS80, and the dealer said it should be ran with 93, as the effectiveness of the octane is reduced already by the the mixing w/ the oil.
  2. bayfish

    bayfish LawnSite Senior Member
    Messages: 641

    I use 93 octane for the mixture. High performance motors need high octane.
  3. ElephantNest

    ElephantNest LawnSite Bronze Member
    from La.
    Messages: 1,878

    They are NOT made for high octane, 87 will do just fine.
  4. o-so-n-so

    o-so-n-so LawnSite Bronze Member
    from Alabama
    Messages: 1,218

    I use 89 octane in everything. I have a 6 year old FS80 that stihl performs great. It has never experienced 93 octane.

    IMO 93 octane is not necessary for 2 cycle lawn equipment.
  5. Keith

    Keith LawnSite Gold Member
    Messages: 3,979

    I use 87 in everything. I just make sure it's from a good station.
  6. mowerman90

    mowerman90 LawnSite Bronze Member
    Messages: 1,491

    They are NOT made for high octane, 87 will do just fine.

    That is correct, they are made to operate perfectly well with 87 octane fuel. However, did you know that 87 octane fuel can have up to 10% alcohol without having it be listed on the pump. 93 octane does not have alcohol because it would be impossible to reach 93 octane if it did. Why does that matter? Because alcohol and 2 cycle oil DO NOT MIX! Ask your local dealer if they've ever had someone return an almost new trimmer for warranty work because it was seized? The reason being because of insuffecient lubrication. A couple of cents on the gallon is no reason to take a chance of seizing a 3 to $500 piece of equipment. I run only premium in my 2 cycle stuff, always have, always will.
  7. drobson

    drobson LawnSite Member
    Messages: 237

    On my echo equipment, the manufacturer recommends 89 octane at a minimum. I believe that is because of the already mentioned alcohol content in the lower octane fuel. Remember that going against the manufacturer recommendations can void a waranty!! Even though it may seem silly with some of the things they recommend, I think it's better to be safe than sorry.
  8. pottstim

    pottstim LawnSite Senior Member
    Messages: 501

    High quality 87 octane. Either Exxon, Amoco, or Chevron.
  9. bayfish

    bayfish LawnSite Senior Member
    Messages: 641

    From off road bike 2 strokes to string trimmers, these motors turn a load of RPMs. I've always used 93. I'm sure they would run on 87, but I believe 93 helps get those RPMs up quicker. Point well taken on the alcohol content. Did not know that.
  10. Lawn Specialties

    Lawn Specialties LawnSite Member
    Messages: 208

    I just bought a new 260s echo trimmer and the manual suggests minimum 89 octane with no more than 10% ethanol.

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