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Stihl fs250 carbon ?

Discussion in 'Mechanic and Repair' started by The Grass Guy, Feb 23, 2010.

  1. The Grass Guy

    The Grass Guy LawnSite Member
    Messages: 69

    I have a stihl fs250 that i purchased new and went to using it on jobs, half way thru the 2nd year and running opti oil mix it up and quit running one day.I grabbed the back up and finished up, not knowing what the issue was i went to the dealer,an employee whispered to un screw the fitting on the muffler and see if it ran,it did and i was told this was common, 5-6 bucks later it was running with a new one and an extra one to clean for a back up. ( not a slide in screen type on the 250 ) The trimmer still has an issue about shutting off after a short while of running,?? is it possible the muffler could also have build up in it causing this ? or which way should i go.The mechanic told me that when i have a shut down problem i should disconnect the shut off switch wire at the coil and run it in case the wire has a short, i still feel that somewhere the carbon build up still has an issue,this year i will run amsoil at 80:1 to prevent this build up.any ideas on cleaning the muffler or where to go and look. I have picked up an fs80 and boy its light compared to the fs250 lol thinking the 250 will be the back up from now on.
  2. betmr

    betmr LawnSite Bronze Member
    Messages: 1,663

    In our place we remove the sparkarrestor and discard it.

    I'm trying to figure out why some guys are going against manufacturers recommendations of 50:1 fuel to oil mix, and opting for 80:1. Seems to me that you are cutting way down on lubrication. You are the second guy I've seen today that is doing that, Why?
  3. RonAyersMotorsports

    RonAyersMotorsports LawnSite Senior Member
    Messages: 854

    Be careful. This will no longer be allowed. If dealers are removing and discarding emissions screens in mufflers they could face fines up to $37,500 per unit and per each day unit was used. Screens must be cleaned or replaced and reinstalled. LCO's running equipment without these screens could face fines up to $3,750 per unit per day of use and if their unit was repaired by the dealer fine goes back to dealer at $37,500. EPA PHASE III LAW!

    Most users of larger trimmers experience carbon build up either from running regular fuel instead of 89 or greater and run a mix other than STIHL. Some users run premium fuel and STIHL mixes and still experience carbon build up over time due to operating equipment at half throttle or less 80% of the time causing more carbon deposits.

    To prevent run premium fuel with a quality STIHL mix and operate equipment at full throttle position as often as possible.

    The FS100RX is our lightest most balanced trimmer even more so than the old FS80's. And it's only $339.95. Or for 2 cycle lovers we're introducing the new FS70R trimmer. A little heavier than the FS100RX but comes in at a great price point of $279.95 for a commercial series trimmer.
    Last edited: Feb 23, 2010
  4. The Grass Guy

    The Grass Guy LawnSite Member
    Messages: 69

    Betmr, I understand what you are saying about the oil and it is not my intention to turn this thread into an oil thread,(god knows there are hundreds on here) I have looked and read everything possible to read,amsoil says their oil will work at 100:1 ,I know i have been getting carbon issues and im looking at different solutions.If needed i could mix it at 50:1 like you would the dino oil but i think it would be too heavy on the oil side. Guys have been running amsoil 80:1 and even 100:1 without any issues,im sure the warranty has expired like mine and they wouldnt do anything to have to throw away equipment due to oil mixing issues. Not saying its for everyone,and I understand people staying in their comfort zones.
  5. betmr

    betmr LawnSite Bronze Member
    Messages: 1,663

    What do you mean by a "Stihl mix" and a "mix other than Stihl"?

    I'm trying to figure out why, in one day, I'm reading about two guys that are running 2 cycle engines on Fuel/Oil mixes of 80:1 When the manufacturer recommends 50:1. Seems to me like a big cut in lubrication.
  6. The Grass Guy

    The Grass Guy LawnSite Member
    Messages: 69

    Do a search for Amsoil and you will find all the oil threads you can stand and maybe your answer.
  7. dKoester

    dKoester LawnSite Gold Member
    Messages: 3,305

    They have their own oil for their machines.
  8. Merkava_4

    Merkava_4 LawnSite Bronze Member
    Messages: 1,441

    What I did yesterday was download all the service manuals
    that were on Walbro's site. I was very surprised to find that
    they were available for download. The information they provide
    is extensive. If anybody is fascinated about carburetors like I am,
    that would be some good reading for you.
  9. South Florida Lawns

    South Florida Lawns LawnSite Platinum Member
    from usa
    Messages: 4,784

    Wow that's crazy on the fines. I thought they're just spark arresters, not emissions screens. That's the second thing I do to all my trimmers/edgers (first is remove trimmer guard). I wonder who goes around checking 2cycle stuff for these things? Maybe that's more of a California thing, seems like a waste of time and money to me, especially with all the clean 4 mix's sold today.

    To the original poster, if you still feel like there's bogging due to carbon buildup take off the muffler and spray some carb cleaner in it and or compressed air and you should be good to go.
  10. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,292

    I would keep the oil mix just like stihl recommends and clean the ports yearly or more if needed. We do that on all our 2 stroke equipment. I want them to last long and that is the reason for not running lean on oil. I seen my first muffler clog the other day and the guy had been running walmart oil for three years on the unit. The ports had closed about 80%. Easy to run unit with muffler off to see if it is causing back pressure.

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