If you chase other video links on that type of saw on You Tube, I think he has it set up wrong honestly. All the others have the saw running parallel to the frame, not perpendicular, the end of the frame is in the dirt on the motor end, and resting on the log on the other end. That set up seems at least somewhat stable. That wore out wheel he has flopping around under there, and the frame not resting on anything solid just really doesn't seem to work well in my opinion.
All of them seem terribly under powered in the videos, but by the same respect, not one of the saws appears to have been sharpened anytime recently. Thus I wonder if they wouldn't work a little better if the saw was properly sharpened. There was one I watched that defied reason, the connecting rod on the crank was external. Apparently the operator was supposed to manually oil it occasionally.
Looks like something one might find in Colin's backyard at any rate!