Aluminum or zinc keys are the vast majority, also in my experience. Nearly
all the small engines' flywheel/crankshaft keys I've seen, which include
probably a hundred or more, Toro, Tecumseh, Briggs and a few other names,
plus some chainsaws, but I believe all the vertical and horizontal shaft
engines were zinc or aluminum keys.
The ones that I'm not entirely certain about are the chainsaw engines.

These engines included some older ones, but they were mostly 1970s or 80s
models.

The blade hubs or output shaft sprockets had steel keys.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Steve W." wrote in message
...

Briggs and Kohler use aluminum or Zinc keys on most of the small (under
7hp) engines. All the ones on push mowers are zinc.