Originally Posted by IRRITECH
I have had some success with the stihl decarbonizer. If the unit is older and you have never done this try it. And like dboyd said adjust the valves. Also if you have a bunch of grease and dirt on and around the carb look at the gasket between the insulator and head. I have recently replaced 2 of them one KM110 and an FC90.
Stihl decarbonizer is that like mechanic in a can