Most interesting find at a thrift shop ever

    This machine was sitting at a thrift shop, a handwritten note suggested it was a steam engine.  Hmmm. two single action cylinders of different diameters, no valve gear at all. 

 It's almost certainly not a steam engine but possibly an homemade experimental heat engine of some sort? There is a propane burner in a rusty box (below) that fits around half of the larger cylinder, the other half of the cylinder is surrounded by a metal trough, maybe with cold water? 

We applied a few pounds of air through the valve on the small cylinder and the flywheel turned a few degrees but no joy...

 Any ideas?