John K Jordan
I don't know about that model, sorry, but it's pretty safe to experiment with the adjustment screws. Just make a little mark lined up with the slot and try turning 1/4 turn in either direction. If it runs worse put it back. If no change or it runs a bit better try turning a bit more but keep up with how much. (I used to even know what screw did what and why but that's long gone from my aging brain!)
I didn't check, but I have found downloadable Stihl manuals for my saws on their web site.