I'm a big Stihl fan, ever since I replaced the head gasket on my BR400 backpack blower with some luck and that wrench they attach to everything they make...8 years and that warhorse still blows leaves every Fall, in spite of my maintaining it.
That said, it has always been a pita to start, especially once it has run a while, and then sat for 10-15 minutes. I have followed all the above suggestions-- fuel/air filters, fresh plugs, and new spark arrester-- and it still demands plenty of "foreplay" before it will fire up and perform.
Whatever...I've never meet a small-gas engine that didn't have a mind of its own. Best advice I ever got about engines, was park them in the sun, and that's certainly true of Stihl.
I own 5 Stihl gas engines now-- 2 blowers, chainsaw, power pole-pruner, cut-off saw-- and wouldn't think to buy a Echo, Makita, or Wacker.
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Good to hear Bladewizard is still kickin'. Maybe I can get him to sell me some blades.