I fixed my Dad's saw a while back. He hardly ever uses it. So I go to bring it home, and he saws how it ran fine when he used it not too long ago.... Kinda like the car and tractor ad's "ran when parked"!
So, I get it home. Fill it up with fresh premium Husky mix and Premium gas. It will not even try to start; this saw always started in a couple pulls. Great spark... Put a bit of gas in the cylinder and it fires immediately, for a second.
While I'm doing this, I hear something rattle, so I shake the saw. Sounds like something in the gas tank! I drain it in to a coffee can, and plunk out comes the fuel filter with a piece of rotted hose! The hose was just mush!
Fortunately, there are three dealers withing a few minutes of here. Got a new hose and filter, put it on, and three pulls later running like a champ.
That was on an older Stihl 024AV. I have had to replace hoses on a Husky brush cutter and Husky backpack blower too. Sucky gas...
FWIW, that is one of my all time favorite saws. The Stihl 024/0260/260 series is a great, well balanced saw.