pump
Get an oil tube kit fron Stihl, it will be a pretty stiff plastic, oops, space age polymer. Remove the brass insert in the old tube by using a screw into the end and pull it out. Slit the other end to remove it from the pump. The push the other end back through the hole in the case.
Cut the new tube as per the instructions in the kit, or, the same length as the old tube. Push the tube onto the pump. Warming the tube will help, or use something to grab the tube THAT WILL NOT CRUSH IT!
Install the spring inside the tube, slide the tube into the case from the inside. A very small chamfer on the end of the tube will help.
Push it through untill you can grab the end of the tube. Use a punch that fits the brass insert to install it in the tube. Push the tube back into the hole in the case untill it is flush with the top of the hole.
Re install the oil pump, worm, clutch and washer, if used, and sprocket parts.
Check for oil out the tube. Use and enjoy!