Based on the Keystokers I have owned I can offer the following:
1. empty the hopper
2. remove the four (or 2, depending on your stove) screws on the side that hold the stoker motor bracket to the stove (edited thanks to Chris
, the one I have here has 4)
3. pull the entire assembly out the back of the slot (motor, and pusher block with the adjustment screw on it), the motor and plastic cam will seperate from the pusher block
4. clean the entire slot thouroughly with a small wire brush and vacuum
5. inspect the small nylon screws on the side of the pusher block for wear, replace if needed
6. reinsert the stoker motor/cam assembly into the pusher block and slide the entire assembly back into the slot.
7. reinstall the 4 screws and verify operation
8. enjoy the warmth!
hope this helps, post back if any problems, have fun!