How do I alter the chain tension?

There is a Pan Head Screw at the front of the saw next to the blade. This turns a tensioning nut that locks into one of the holes in the chain bar. It turns clockwise to tension, and anti-clockwise to loosen.
If the screw isn't there, the pan head nut won't be either, not will the sleeve which goes on the Pan Head Screw as a spacer.
(The Pan Head Screw is a M5x50)
Stihl part number for this are:
Pan Head Screw 9043-319-8100
Sleeve 1120-664-2600
Pan Head Nut 1120-664-1500

mike
May 2006