Grasshopper ignition switch used in most tractors with Briggs, Kohler Command, and Onan engines with magneto (not battery) ignition.
5/8 inch mounting hole. 3 position switch with 5 terminals-SBMGL.

Used on many other applications including John Deere, MTD, Murray, Scag, Toro, Noma, Bobcat, Cub Cadet, Roper, Honda, and AYP.