96 evinrude 25hp throttle stuck suddenly

Wow, am I stuck. Went out, left dock as normal. throttle a little fast in no wake. let off tiller, once boat slowed I tried to turn the throttle again and it coughed and died. No matter where the shift position is, I have no ability to turn the handle. Disassembled handle and found no trouble. disconnected the opposite end of cable and the handle turns fine. Issue seems to be from the shaft that goes up to the thin lever that goes to the carb and the rest of the parts under the flywheel. It also would not restart when this all happened and is back firing. There was a small machine head bolt and square sided nut that were laying in the bottom of the engine case.
I can not, for the life of me, figure out how it is supposed to work.