Hi Jack,
That is an excellent site.
I have either a Cooper or Johnson iron horse.generator.
I think the Coopers on mowers (the OP's rreason for this thread) would have been the bigger ones not this little one. It would run a small shearing machine but that's about all.
Cooper had many many engines even Ronaldson Tippert and Kirby.
Interesting the tie up with Sunbeam and even Victa eventually.
A wonderful store of knowledge.
Jeff