I swear I must be getting senile or … maybe my regulator is bad. Been doing jewelry work a long time (50 plus years) … been here forever. Sigh … miss Orchid … anyway. I just do jewelry work sort of now and then these days … now and then being about a year ago. You don’t really need the back story, but you are going to get anyway because you are the only friends I have 
I go to the gym daily. I have been married for lets see … 43 years now. Neither my wife nor myself wear a wedding ring … rings of all types just drive us nuts … I worry with it all the time. I’m old and very ugly, but I guess some ladies like old and ugly (if they smell money). Anyway, this “person” has shown an unnatural interest in me and I feel the need to wear a wedding ring … not just for her but to put it out there I am taken. So I decide to make myself a simple silver one. Easy enough. Then I go to solder the band together … and I can’t seem to make the damn torch work like I remember. For reference its a Acetylene B tank with a Smith tip. I open the tank valve a bit and it pegs both the tank dial and the tip dial. I’m like … must have left the regulator open. Turn off the tank. Close the regulator (I think) you know clockwise. Bleed the line. All good. Regulator fully clockwise … down. Open the tank … instantly both needles peg maximum. I opened the regulator (counterclockwise) and managed to control the flame and get my silly little job done. What is going on? Am I losing it? I open the regulator (counterclockwise) and it adjust the damn flame. I am either losing it … or something else it going on. So … verify I am not going nuts. To light this torch … you have tank valve off. You have regulator valve fully clockwise. You open tank valve a bit … at which point tank valve goes to max. Regulator indicator should be zero. The you open the regulator counterclockise to dial in the pressure you need … right ???
Let’s see. Hopefully, I’m reading all of this correctly.
First to turn the B tank on at the tank turn the valve 1/4 turn to the left or counter clockwise. To adjust the Smith regulator you either have a T screw or a red knob. Probably you have a T screw. That’s most common. Screw the T screw out until it’s loose to turn the gas off. (loose, not all the way out to where you’re holding it in your hand) Screw the T screw inwards to turn up the pressure.
More modern Smith regulators have two sets of pressure gauges. One shows the pressure in the tank. The other shows the pressure in the line. If you only have one pressure gauge, then it’s only showing pressure in the tank. I hope that make sense!
My guess is when you are turning the torch on and off there is still pressure in the line and that is messing everything up for you. Like you think it’s on because it fires up, then it goes out because you’ve used up all of the pressure in the line. Do you think that’s your problem?
No matter what to get things back on track you need to do this:
Close the gas off at the tank. Then bleed the line until there is zero gas in the line. Then back off the T valve to where it’s loose. Turn on the gas on 1/4 turn. Screw the T valve in until you have about 5 lbs pressure. Light your torch and fix your ring.
It’s really hard to diagnose issues like this with just written words, so hopefully this explains it!
Finger crossed!!
Jeff
Take it to a welding shop to make sure that you don’t have an accident waiting to happen…Rob
Rob is right! Don’t fool around. This is something that requires in person diagnosis. Get it checked out by a welding shop or buy a new one. It’s about $120.
Big thanks to Rob for pointing that out! Sorry that I missed it at first!
Acetylene is unstable at pressures higher than 15 psi. You don’t want to be messing with acetylene and a regulator that is giving inaccurate readings.
Jeff
You said you’re turning the regulator handle clockwise? If you’re looking at the regulator so you can read the dials, you should turn it counterclockwise to turn it down all the way (off), until it’s loose, as someone else said, before you open the tank. Turning the T-handle clockwise turns it up and it’s dangerous to open the tank like that. Probably would be best to take it to a welding shop as others have suggested, to make sure nothing is wrong.