The 5HP Briggs and Stratton engine on this 1993 MTD Yard Machine rototiller stopped working, was disassembled, and then was left outdoors for a winter. Earned $40 honest pay for rebuilding the engine from a trashbag of parts. Rebuilt the carburetor and had to remove significant rust from the gas tank with phosphoric acid, but now it runs fine and is back in use.
Did some searching online to figure out the governor linkages, and found some links that might be useful to anyone else working on this same engine.
MTD factory parts and parts diagram
Full diagram of tiller, part numbers