Komatsu PC75uu-2 Starter Problem

1. My 1994 PC75UU-2, Serial number 8310, Engine Model # 4D95L-1, was getting harder to start. I replaced the batteries but still turned over slow. Had a friend try and start while I watched and fire/smoke came out of the rear of the starter motor. Now it won't turn over at all. I suspect the armature is dragging on the field coils. I need to remove the starter and don't have the service manual.

Do I have to take the counterweight off to access the starter, or can I remove enough linkage...

Komatsu PC75uu-2 Starter Problem

Komatsu PC75uu-2 Starter Problem