The pulley is just slid onto the armature shaft and the woodruff key is to keep the pulley from spinning on the shaft. Set it upright and use penetrating oil on it and let it sit. If your dealing with a stamped steel pulley its tough to use pullers as it will probably bend if stuck on there good. You may want to try using a couple of screw drivers and pry upwards on the back side of the pulley. If your going to take that woodruff key out as well you will want to use a blunt nose punch and knock the back side of the key, the end closest to the armature windings, down into the armature shaft, this will raise the front of the key upwards out of the shaft, you can then use a screw driver and get underneath the front of the key and knock it upwards and it will usually pop out. Let us know how it works out with the pulley.
