9U10398 is a 1952 model.
Looks like there was a electric starter added to the RH side of the pony motor. I see the belt, adjustment bracket and fabricated mount.
There was a starter on it, which is getting rebuilt or replaced (depending on what’s wrong with it. The link is of the starter we might rig up. It sucks fighting with the pony with a pull start. www.amazon.com/STARTER-GENERATOR-FITS-Ya...k&pd_rd_i=B004SBPIOK