New 4 Mix engines

Discussion in 'Lawn Mowing' started by Chris G, Jun 5, 2008.

  1. Chris G

    Chris G LawnSite Member
    Messages: 95

    From what I hear from my Local lawn mower shop is that the New Stihl 4 mix engines have been on the fritz and seemingly in the shop very often. Has anyone had this problem?
  2. bjack312

    bjack312 LawnSite Member
    Messages: 0

    I have not had a problem with mine, starts easy and has tons of power. The only gripe that I have is that the throttle response is pretty poor compared to the 2-stroke stuff.

    Was talking to my dealer when I purchased my edger, and he said that Stihl had some problems with them when they first came out, but that this has been corrected. The problem was apparently due to grease that they used in the engine when assembled.
  3. AmsoilPower

    AmsoilPower LawnSite Senior Member
    Messages: 938

    Most issues have been from excessive carbon build-up on the cylinder head and valves. Check into the Amsoil Saber Professional for virtually no carbon build-up.
  4. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,370

    No offense but if I bought a BR600(which I won't) I would darn sure use the oil that they recommend since this engine is still risky. And yes I understand that you are very very confident that your oil is better but this is a special situation.
  5. Ridin' Around

    Ridin' Around LawnSite Senior Member
    Messages: 266

    Check out the br600 thread from last week. We discussed the oil needs of the Stihl 4 mix engine in detail. Ed is right, this is a very special situation and exactly where a premium oil like Amsoil is perfect for the Stihl 4 Mixes. Take a read of the thread and make sure you read the part (my post) :clapping: on the ratings for oil and why those are more important than a brand.
  6. 4.3mudder

    4.3mudder LawnSite Silver Member
    Messages: 2,227

    I used to work at a Stihl authorized dealer. The problem I encountered while working on them was that the ignition modules would go out. It was hard to believe. You could check for spark, and it would get spark, but not at the correct time. Other than that a problem I have with them is the throttle. You don't have that "mid range" it has a sharp increase in RPM from low to high. Thats the problem that I have had with using them. I wnet back to using FS250's, only 4mix I have now is BR550 backpack blower, but I have not had any problems with it. Good luck
  7. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    They're not new, I've had my fs100rx for 3 years now, the br600 I bought last year...
    I won't brag about never having a problem, but nothing beyond what to me is normal wear and tear.
  8. stuffdeer

    stuffdeer LawnSite Bronze Member
    Messages: 1,617

    I bought the FC95 Edger, FS100RX, and BR550 this year, I've used them since the beginning of the season, at least 4 days a week, and absolutely LOVE them.
  9. M&M Mowing

    M&M Mowing LawnSite Member
    Messages: 113

    Ive got three of them, and had one of the 110 trimmers for about four years. Great trimmers, good balance and power. The engines themselves are very neat machines, I talked to a stihl rep at a machinery show and he showed me how the engine oiled its internals. The only problem that I can think of is how the engines need a valve adjustment and the ignition modules as stated in an earlier post. The trottle cables on the trimmers usually last about two years for me until they break.
  10. delphied

    delphied LawnSite Silver Member
    Messages: 2,067

    My Stihl br600 is light years ahead of my 2 stroke stuff in the power and comfort. Im going to Stihl when my Redmax and Shinny go bad.

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