Originally Posted by Done it

Quick, is the trick. I use a 12Volt impact gun on saws that have a nut face on the clutch, 1 or 2 clicks and it's off. On others use a bolt or flat punch, sharp hit, move around, hit again. If it's not off spray it with wd40 or something and try again later. Don't use air gun. There usually is an arrow or something but you have to go clockwise, hit to the front of the saw. Stihl sell a good, plastic piston stop for about $12, part no: 00008935903 A.