Re: Johnson 20 hp woodruff key
Not sure what you mean by the ignition coils being in the way.
However, I just replaced a key that was sheared in a 1984 35HP. My key was moon shaped, so I took a chisel and very carelly tapped on the top of the key creating a seat for the chisel end. Once I was confident enough that the tool wouldn't slip, I hit the key piece harder and it rocked right out because of its moon shape.
Torque on my motor was 100 to 120ft lbs. Not sure what yours is, but probably around that spot. Torque is important as you timing is based on the taper of the shaft meeting the flywheel.