Hi, y'all,
I am wondering whether it is an isolated phenomenon that I am experiencing.

One of my M1950 is by Coleman, while the other is by Rogers. I find three aspects of the stoves interesting:

1) Both stoves will bleed by itself after shutting off. I am guessing that this is probably not intended by the designers. I do not mind having the fuel tank depressurized automatically, for I usually do it manually after each use, anyway. This "feature" does not present any problems during operation at all.

2) When the valve is pointed to middle, the flame gradually decreases to death. Then you can hear the air hissing out. I find it interesting how it is engineered to bleed only air but not the fuel. Maybe I failed to notice another hole on the stem that stays above the fuel level.

3) The Coleman's output stays the same, no matter how hard you pump, but Rogers will increase its output proportionally to the pump strokes. Rogers can produce a flame that can reach 9 inches high in the dark. And this baby can boil a liter under 5 min., despite it is rated at 5500 BTU! All this is done without producing any soot. One difference is that the Coleman's flame is bluer than Rogers'. And the flames from both stoves are invisible in daylight.

Has anyone seen such?

In regards to point number 2, the middle position (or light) mixes the pressurized air in the tank with the liquid fuel to create a fuel mist. This aids in the lighting of the stove as is won't be spewing liquid fuel out the jet. Once the stove is hot enough to create a vaporized fuel you turn it to all the way left (on?). Now you're running straight liquid fuel (being vaporized of course by the heat). And the air is only supplying the "push". In the "light" position the tank looses pressure rapidly as your are using up the air in the tank.

Another of Mr. Coleman's great ideas. Used in some form or another in many of Coleman's petrol stove's and lanterns.

As for the comparison to the Coleman vs Rogers, I can't say but my Rogers does behave much like yours.

Great little stove.

-franco

My Coleman will lick the ceiling of my garage with flame when I begin to preheat the unit! ( That's about 6ft!)

Scared me once.

Now I take it outdoors for the preheat pyro show.

Cheers!

The pyro in you is happy to see that fountain of flames.........

.......come on admit it.......


Sounds like your 1950 has a problem with the air/fuel tube assembly.

See another chance to fettle.

-franco

Your first quirk isn't actually a leak or blead. When you use a 1950 petrol stove, much of the air you pump in is burned initially when priming the stove (valve in middle position). Even if you add more pressure later, most of the stove's pressure comes from the heating of the gas in the tank. The 1950 gets pretty hot. When you shut down, the gas cools and contracts, it's vapors re-condence and the pressure drops. An Optimus 8r will also de-pressurize this way, even if you use the midi pump. This is entirely normal for self pressurizing or semi-self pressurizing stoves like this.

A stove with no pressure in it is also unlikely to leak in your pack. A nice feature.

If you were to vent an 8r when it was still hot, upon cooling you'd find a slight vacuum in the tank. The 1950's pump would admit air thru the check valve, so you won't get the vacuum in that one.

You could spend a lifetime looking for that "leak" and never find it.

Enjoy your 1950. Good stove, too bad it ain't got no throttle.....

J

You're bang on about the adjustability of these stoves.

On or Off.

Simmer I don't think so.........

-franco

I find it eminently possible to simmer by letting the knob point to the middle and let the air out to my satisfaction, and then turn it to the left to simmer with reduced flame. After a while, I add one or two strokes as necessary.

Works pretty well.

I grow fond of M1950 day by day. I am extremely pleased to find that, when pumped up hard, Rogers (not Coleman) can do one liter of 60 degree Fahrenheit water to a rolling boil in 3.5 minutes in a 7-in pot--as good as Nova or Omni.

I will sing my praises to whoever designed it.

and ruin my PYRO show!!??



remind me to NOT let you touch my 1950...

Yeah, you can always simmer that way. Not quite like an 8r or anything, but it works.

Mighty hard to get the pancakes just right that way tho...

I love my 1950 too, it's one of my 2 regular users. I just wish it could simmer easily and I wish it had a pump return valve lock like a coleman. A leaky return valve on these is exciting.....

You bring up a important point. I have wondered how I would devise a way to keep it dry in transit. I can imagine easily how exciting thing could get...

My thought was to have a length of a rubber band that hooks on the long end of the knob and wraps around clockwise once or twice and then hooks on one of the legs. That way, at least there is something.