I have an older Yazoo high wheel mower with an 8HP Briggs. The mower had been unused for many years and took a thorough cleaning to get it running. It's a pretty impressive mower, but my wife cannot start it; too hard and awkward to pull. As it is an older engine, can I add an electric starter to it? Horizontal shaft, for what that is worth. I am quite capable of any of the mechanical stuff, (changing a flywheel to one with a ring gear, I'm guessing.. ) plenty of tools, pullers, etc.

Take a look at Home - Briggs & Stratton and find out if there was a flywheel with a ring gear for that engine. Look on the blower housing for a bunch of stamped numbers which you will need like model and type.

I recently looked at a site that was talking about Tecumseh conversions and they had one comment. The block had to have the holes for the starter. Both 120 VAC and 12 VDC were options.

You should be able to change it over.