New Stihl FS90 Amsoil Saber?

Discussion in 'Lawn Mowing' started by fastr1, Jun 17, 2010.

  1. fastr1

    fastr1 LawnSite Member
    Messages: 6

    I am purchasing a new FS90 4 mix and I use and sell Amsoil to all my friends however is the 4 mix engine safe to run at 100 to 1 like conventional 2 strokes that I run it in? I know the Amsoil is great however I have read posts that people are running these at 50-80 to 1.

    Since if something happens it would be a rough warranty claim i'm sure.


    IOWA GUY LawnSite Member
    Messages: 60

    It's much better to run to much oil than not enough.
    If you run to much oil it will "foul" a plug.
    Not enough oil and you may seize a piston and the games over.
  3. Alan0354

    Alan0354 LawnSite Platinum Member
    Messages: 4,450

    Lots of people use 75:1 with good result. I use 60:1 myself.

    IOWA GUY LawnSite Member
    Messages: 60

    Alan has anyone ever told you that you look a lot like Sarah Palin.:laugh:
    Yes,your HOTT!!!:laugh:
  5. Alan0354

    Alan0354 LawnSite Platinum Member
    Messages: 4,450

    :p :p :p :p :p :p :p :p :p :p :p :p
  6. Roger

    Roger LawnSite Fanatic
    Messages: 5,933

    I use Amsoil, 75:1, in my FS90R. When it was new, I ran through a few tanks of fuel at 50:1, then moved to 75:1. Did using a richer mixture while the engine was new help with longevity? I don't know.

    I use the same mix for my Stihl BG85 blower, HS80 hedge clipper, and FC85 edger - all three are 2 cycle.
  7. WH401

    WH401 LawnSite Senior Member
    Messages: 572

    I have used Saber at 80:1 w/ 89 gas since my 90 was new and it runs like a champ. The biggest reason most LCO's run 80:1 instead of 100:1 is because most LCO's use a lot of two-stroke mix in the course of a week. The simplest mixing method is dumping an 8 oz. bottle into a 5 gal. can of gas. That and while 80:1 is still a much lower concentration of oil, it still gives you a slight gap between the recommended 100:1.
  8. MikeKle

    MikeKle LawnSite Platinum Member
    Messages: 4,253

    I was all excited about switching to Amsoil, before I found out about the shipping cost! I was going to buy a couple quarts of saber 2 stroke oil, and the shipping was near $15.! Screw that,. I will just keep using the echo power blend. Do you all have another way of getting your amsoil other than shipping?
  9. Roger

    Roger LawnSite Fanatic
    Messages: 5,933

    MikeKle, I can get Amsoil products from the local NAPA store. I don't know how universal this practice is found. Might be worth a try.
  10. Andyshine77

    Andyshine77 LawnSite Member
    Messages: 147

    Result of running a gallon of Amsoil at 100:1 in an MS441 chainsaw. The saw was tuned correctly. The cylinder had aluminum transfer, and both the piston and cylinder were dry with no oil film. The saw was still running fine before tare down. however as you can see failure was imminent, If you look closely, the piston crown also has erosion do to over heating. Sure you can run Amsoil at 100:1 but premature engine failure will be the result every time, I've seen similar results with Opti 2. Amsoil is in fact a good group IV PAO oil but only when ran at more reasonable mix ratio like 50:1. It's also not a top of the line group V Ester based oil.

    441 piston..jpg
    Last edited: Jun 23, 2010

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