fettling

Fettling = working on an old pressure lamp or lantern. In Europe this might mean Primus, Petromax, Optimus, Tilley, etc. In America this means Coleman.

I have a ratty old 1961 lantern (red one on the right) that burns great but has been difficult to light. Hey, it's older than I am and start a little slow in the mornings, too.

Should work like this:

1. fill with fuel
   
2. pressurize with the pump
   
3. crack open the fuel valve about 1/4 turn and listen. You will hear air hissing. Then after a few seconds you will hear fuel start to make a delicate gurgle sound. Close the valve.
   
4. get your match/lighter/torch in there
   
5. re-crack the valve 1/4 turn
   
6. gentle "foof" as the fuel ignites. The mantles start to glow.
   
7. when mantles glow gentle, increase the fuel delivery
   
8. the generator gets hot enough to vaporize fuel efficiently and you get a soothing hiss and brilliant light. All is well with the world. Or the back porch, at least.
   

But it has been working like this:

1. fill with fuel
   
2. pressurize with the pump
   
3. crack open the fuel valve about 1/4 turn and listen. Just air. No fuel.
   
4. wait. wait more. Still no fuel. %&^#*&^!
   
5. Get annoyed and open the fuel valve a couple of turns until fuel does begin to flow.
   
6. floods or semi-floods the lantern as fuel at the 1/4 turn position is metered differently on purpose.
   
7. get your match/lighter/torch in there
   
8. dramatic "BOOF" as the whole top half of the lantern ignites. The neighborhood start to glow.
   
9. if nothing (important) nearby is on fire, attempt to regulate fuel delivery until the generator warms up and things normalize.
   

The part that I needed to work on is hidden inside the fount (the metal base where the fuel is held/pressurized). This part, the fuel/air tube, serves partly as the fuel pickup mechanism and as a kind of crude carbureter. I cleaned the f/a tube and re-stretched a small spring that's part of the carbing process. Starts immediately now.

Here's a pretty good explanation of how it works.