Gary:
Nix the idea of replacing the O-ring in the check-valve. I was thinking both versions of the Whisperlite. Sorry about that. In terms of the Pocket Rocket, you'll probably be able to do some tinkering, but refer to your instruction manual for that. Or, call the manufacturer or, call/visit a local REI store or Eastern Mountain Sports store. Store staff will be able to help you out.
Mav
