Geezak

I have a set of Harris regulators on a cutting torch and both are completely closed but when I open the supply valves both gauges peg out. I removed both and blew them out and made sure nothing was in there and still the same problem. I'm new to all of this and have a great deal of respect for the equipment since it could easily....... BLOW UP! Common sense tells me there is a spring in there but if that was bad, it wouldn't open. When i unscrew the knob it just comes off, i can depress the little metal piece in front of the spring without a problem. This tells me its not seating at all, which doesn't make sense to this challenged wanna-be metal guy. I'm just wondering if this is something that can easily be fixed or should I get a pro involved?