I have the needle tool, and the key, attached to the rest of the stove with a chain. I see how you use the key to adjust gas flow and lift the stove in and out of the housing. But I don't believe I've seen this stove in operation since some time in the 70s, and I want patting attention at the time.
Ah. I figured you were an old hand at these, Rudi
BTW, Unworthy1 has a good point. The fuel in the tank may be just fine. It doesn't degrade like regular gasoline. Or as much. I think I would still change it out since it's been in there so long. Coleman fuel is cheap.
So, here is instructions from one of many sites. Like this guy mentions in his preamble, not shown, I also learned this method from my copy of The Complete Walker. Another great book.
Make sure you rotate your pot supports (three small “L” shaped pieces of wire which look like they are made from cut-off nails) inward, as it is difficult to do once the stove has been lit.
Open the control key fully, and blow across the stove just underneath the burner. Opening the control fully activates a “pricker” wire which clears the burner jet of any potential blockage, and blowing across it will eliminate any detritus in the area.
Close the control key fully, then open it a ¼ of a turn.
Now, take a small piece of paper, a Kleenex, or, if you are Mitt Romney, a dollar bill and light it.
Hold the concave bottom of the stove’s gas tank directly above the flame, so that the flame is touching the bottom of the tank. The idea here is that you are heating the gas in the tank, which will cause liquid gas to expand and run out of the nozzle (jet), and down the vaporizer into the primer pan. Some users simply apply the lighter directly to the bottom of the tank, but before you use the new pencil torch you got for your birthday, or some other semi-welding or soldering implement, remember that not much heat is required and that you are working with a brass tank filled with gasoline. In short, don’t get cute with innovations.
When the primer pan is full, close the controlling key completely, and set your stove down on the paper remnant to assure it is extinguished.
Light the small pool of liquid gas in the primer pan, and avoid the natural impulse to run away in a panic which occurs when you realize you have set the outside of your gas tank on fire!
After 15 or 20 seconds, the flame will begin to atomize the gas in the vaporizer, and will also begin to pressurize the stove’s tank. You will be able to hear small “jetting” noises, but resist opening your control key before the entire pool of gas in the primer pan is consumed as it will result in a weak, guttering flame.
Just before the priming flame dies out, open the gas valve and it will ignite the now-atomized gas shooting out of the nozzle with a pulsing roar. If you miss the window, have a match or small lighter at the ready. The stove will continue to pressurize itself for as long as there is gas in the tank and the flame is maintained.
The “pulsing” roar is normal for this stove.
The burner ring will heat to red, but will not melt. Once the ring is red, it will automatically relight the burner if it is extinguished by a gust of wind.
Avoid trying to simmer until after the burner ring has reached temp.
EDIT: BTW, Rudi, these instructions assume the later variation with the self-cleaning needle built in to the head/nozzle. Your model 71 doesn't have one. Just use your little pricker tool to clean out the nozzle prior to firing.
DEMYSTIFYING THE SVEA 123 STOVE, by Rand Rasmussen