Picked up a Champion mfg in Minneapolis. According to what I can gather from Conrad’s book, it is between 1935 – 1946 and most likely 2 hp. Please review the attached pictures and reply with any information per this motor. A parts list diagram would be wonderful.
I’m sure that someone on here can pin it down from the pix, but for me , model number will help. Look around on the crankcase for a number. Oh’ that particular model is affectionately known as the “bed pan” motor.
Somebody already Id’d your S1F as a 1940 Kingfisher single over on FB. BTW, these were Champion badged motors built by Scott-Atwater. The postwar Champions were the real ones.