I do maintain the whisper lite. It wasnt pressurizing and I was using white gas.
Usually you need to replace the o-rings at a minimum or the pump entirely when that happens. The O-rings do fail after a while, but are meant to be easily replaced.
What year Whisperlite is it by chance? My Whisperlight doesn't work that great in the really cold weather, but it's a older model. The oil and leather o-rings freeze up, but I hear that the new models are much better. I think mine is from 1996. I haven't used it for several years now, but keep it since it's a really good one to take overseas (I also have an XKG).
We also have the powermax fuel in a local ]bike shop so ill have to stock up on that.
It works awesome in cold weather, but make sure you have the right stove for it (only a few stoves take it). If you leave the cannister out all night in winter, it will still fire right up in the morning (performs flawless at least down to -23F). I bought a 10 year supply when I heard it was going to be phased out.
I'm slow and fat. Unfortunately, those are my good qualities.