That is a bummer on Stihl, that was (and probably still will be) my next chainsaw. The Germans know how to build them.

This will sound nuts, water and a carbs, but I do my carbs in a ultrasonic tub with warm water and sea foam motor treatment. Works very well, I leave rubber and plastic on as well. Then take a set of O/A torch tip cleaners and go through it, then high pressure air. Works wonders for sure. Will even get varnish gas out or loose.

I killed a Ryobi 2 stroke carb with carb cleaner once. Ate the diaphragm up on it and in no time I might add.