I was given another strange looking homemade steam engine contraption as a birthday present. Im pretty sure I saw this one on eBay recently. It looks like the second cylinder was ported to be a compound cylinder then plugged and incompletely reworked to be an air pump. The stroke is approximately 1.2, the cylinders are roughly 1.25 with 2.2 inches of stroke ability.
The engine was make runnable after some quick modifications to the working valve cylinder. My plan is to run it on steam so I started by building a 2 throw crank to use the entire cylinder and it ran fine on air. I am calculating the bore for a primary cylinder and will sleeve to fit. The valve cylinder was poorly made, too small, binds and will need to be replaced. Also need to address bearings.