I have the same cane, and when I got it it wouldn't run at all.
Returning it would have cost about as much as I paid for it, so I had a go at fixing it.
I made a new piston to replace the sloppy, very undersized original one, lapped the port face, and it burst into life at under five pounds of air pressure. I spent about 45 minutes on these repairs.
Happy with it now.
Good thing my very low offer was accepted by the seller!