M1950 questions

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TunkTop
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M1950 questions

#1

Post by TunkTop »

I the proud new owner of a M1950 single burner stove by Coleman. I have other single burner and suitcase stoves by Coleman as well as some Primus/Optimus/Svea stoves, so I understand stove construction and operation to some degree. However, with neither manual nor parts list, I am forced to make some assumptions about this fettle. Perhaps those more knowledgeable would be willing to guide me.

Since there is no filler cap, I presume that the pump and pump tube are removed for filling. That is presently a problem for me because despite cranking the knurled ring out as far and as hard as I dare by hand, the tube will not budge. Is there a petrified gasket between it and the fount that is welding the two together? If so, any suggestion for getting it to release? I have applied Kroil for a few days, but I have never used it for anything except metal joints in the past.

The priming wick is pretty ragged. Is there a source for small diameter fiberglass stove gasket?

Does anyone use alcohol to preheat?

Does this stove have any “throttle”, or is it all or nothing?

Hope I’m not being too much of a PITA.
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Emorr123
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Re: M1950 questions

#2

Post by Emorr123 »

There is a gasket under the lip of the pump tube. As far as getting it off maybe wrap it with some leather and gently use pliers to break it free. A little heat might do the trick too.
Some people have used tiki torch wick or fiberglass rope
I’ve never used alcohol. Just open the valve and let some fuel run down into the cup to preheat
They are pretty much all or nothing. Feisty little stoves that sound like a jet and rip it up🔥
Also if you haven’t already, there are spare parts in the pump...unscrew the pump handle.
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Re: M1950 questions

#3

Post by Emorr123 »

Eric 
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TunkTop
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Re: M1950 questions

#4

Post by TunkTop »

Eric, Thanks very much for helping me out. I will try these suggestions.
I had actually considered pulling the burner and using the compressor to pressurize the fount...
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Re: M1950 questions

#5

Post by TunkTop »

Can’t wait to make brew a cuppa on this puppy.
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Coldwaterpaddler
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Re: M1950 questions

#6

Post by Coldwaterpaddler »

If the stove is missing the instruction label, see if you can find a photo, either here or on the web. If the seals have been replaced recently, all you need to do is pump 10 times. Open valve for 3-5 seconds, close valve (this will allow the gas from the vaporizer to run down into the preheat cup), light the preheat cup. After a minute but before the flame goes out open the valve to light the stove. If you get a big flame instead of a blue flame it just means that you needed more fuel to pre-heat. That's pretty much it.

I only use the stove fuel for preheating, and never alcohol.

Change the cap gasket and air check pip (seal) if that hasn't been done as far as you know.

There is one other seal that goes bad which will prevent the stove from shutting down properly, or leaking when it is stored/transported. That one is a pain to replace if you've never done it.
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mcdugal2
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Re: M1950 questions

#7

Post by mcdugal2 »

This is the hard one to replace..
ImageIMG_1296 by Philip Rhoades, on Flickr
It is located here in the valve..
ImageIMG_1295 by Philip Rhoades, on Flickr
On the Coleman the instruction sticker is under the valve knob on the opposite side from the logo and pump cap..
ImageIMG_1291 by Philip Rhoades, on Flickr
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mcdugal2
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Re: M1950 questions

#8

Post by mcdugal2 »

Oh and this what you might find inside the pump...
ImageIMG_1292 by Philip Rhoades, on Flickr
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Re: M1950 questions

#9

Post by Optimus45 »

I’d be very careful using heat on the pump tube. The bottom of the tube is soft soldered on and can easily come off. Don’t ask me how I know. Actually I better tell you I did mine with a heat gun and it still unsolder.
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Re: M1950 questions

#10

Post by HercL4D2 »

You can get a gasket rebuild kit here but it is closed until March 10. https://fettlebox.co.uk/index.php
TunkTop
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Re: M1950 questions

#11

Post by TunkTop »

Wow! What a great group of guys...lots of good info here.
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JimL
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Re: M1950 questions

#12

Post by JimL »

When removing the valve from the fount to get at that tiny O-ring, make sure you don't put pressure on the valve stem itself. I failed to do this on one and snapped it. Another suggestion is to make certain you're keeping the fount perfectly straight for removal. The top of the fount is easy to bend if you don't, but is at least also easy to bend back if this happens. To be clear, you don't want this to happen.

If debating whether or not you want to replace the O-ring in the fount, know that if/when it fails, you will not be able to shut the stove off. In that case, I guess you could smother it by covering it with a bucket, or just wait until the stove runs out of fuel.

If not already familiar with the "Born to Boil" M-1950, you'll appreciate how fast it'll boil water. When perking coffee, I use one to get the water hot really quickly, and then move the percolator to a 502 which is extremely adjustable.
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Gunhippie
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Re: M1950 questions

#13

Post by Gunhippie »

The M1950 is easily adjustable from this:

Image

to this:

Image

In other words, all or nothing. You can get a little less heat by not pumping it up much.

Here's how I remove the valve to get at that little o-ring:

Image

I didn't find the ring hard to remove and was able to find a replacement Viton o-ring at Ace.
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Re: M1950 questions

#14

Post by macwacs »

Some times the pump tube itself gets crossion on it (outside of tube, inside of the fount)and can be a real PIA to remove. I have a friend who ruined two or three. In that case pull the entire valve replace the donut gasket and give the fount a critus bath over night to remove any gunk/corrosion from the pump tube. Then they come out easy & simple. Referance to Original post.
RMW
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Re: M1950 questions

#15

Post by TunkTop »

macwacs wrote: Sun Mar 07, 2021 2:01 am Some times the pump tube itself gets crossion on it (outside of tube, inside of the fount)and can be a real PIA to remove. I have a friend who ruined two or three. In that case pull the entire valve replace the donut gasket and give the fount a critus bath over night to remove any gunk/corrosion from the pump tube. Then they come out easy & simple. Referance to Original post.
RMW
Hadn’t thought of corrosion, just assumed the gasket was the problem. Thanks for giving me a second perspective.
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sleebus
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Re: M1950 questions

#16

Post by sleebus »

For what it's worth, I did a little video on one. They're pretty cool stoves.

Check out my channel at GasUnderPressure
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Re: M1950 questions

#17

Post by macwacs »

The more they are run the better they get. I use mine almost daily for the morning coffee.
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Re: M1950 questions

#18

Post by JimL »

>>For what it's worth, I did a little video on one. They're pretty cool stoves.

Nice job on that video. Personally, I've only seen the generator clips for the spare generator attached on the inside of a leg.
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Re: M1950 questions

#19

Post by sleebus »

JimL wrote: Mon Mar 08, 2021 6:20 pm >>For what it's worth, I did a little video on one. They're pretty cool stoves.

Nice job on that video. Personally, I've only seen the generator clips for the spare generator attached on the inside of a leg.
Thanks. Yeah, that makes more sense for sure. This one came with it on the outside, go figure!
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Re: M1950 questions

#20

Post by TunkTop »

TunkTop wrote: Sun Mar 07, 2021 10:41 pm
macwacs wrote: Sun Mar 07, 2021 2:01 am Some times the pump tube itself gets crossion on it (outside of tube, inside of the fount)and can be a real PIA to remove. I have a friend who ruined two or three. In that case pull the entire valve replace the donut gasket and give the fount a critus bath over night to remove any gunk/corrosion from the pump tube. Then they come out easy & simple. Referance to Original post.
RMW
Hadn’t thought of corrosion, just assumed the gasket was the problem. Thanks for giving me a second perspective.
Well, I ordered a gasket kit from Mike, since I really didn’t like the idea of potentially not being able to turn the stove off. The strap wrench made pulling the valve pain free.
I found rust in the bottom of the fount, so I think Macwac was onto something with the possibility of the pump tube being rusted to the fount. I didn’t have any critic acid immediately available so I filled the fount with evaporust and tilted it so the tube was submerged. We will see if that makes any difference.
Really looking forward to getting this thing fired up!
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Re: M1950 questions

#21

Post by macwacs »

Some of the early M1950 stoves were iron and did indeed rust. Looking at your first post I see the date on the stove & might be an iron fount as well as other trimmings. See if a magnet sticks. The later made ones are stainless steal and anti magnetic. I dont know when they switched but most 1960 and later seem to be S-S.
By the way good looking stove. Brewed my morning coffee today on my dog of a 1966.
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Coldwaterpaddler
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Re: M1950 questions

#22

Post by Coldwaterpaddler »

A magnet sticks to all of my M-1950 stoves so it doesn't appear that any are austenitic stainless steel. Were there some that were non-magnetic steel, like the M-1942 Mod, and if so, which ones? Or, are you saying that they are made from a ferritic stainless steel? I've got stoves that span from 1951 to 1983 but certainly not everything in between and all of them have at least some rust on them. So, I'm curious about what I dont have.
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Re: M1950 questions

#23

Post by macwacs »

My mistake. Just did a run with a magnet and they do stick on all of the m1950 to 80 produced stoves. I had to do some magnetic test on some military gear this last weekend and got mixed up not looking at my notes
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Re: M1950 questions

#24

Post by Coldwaterpaddler »

Well, there are several types of stainless steel, so you may not be wrong. I really don't know which steel was used, except likely not austenitic stainless steel.
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Re: M1950 questions

#25

Post by macwacs »

I just did more investigating. Some pot supports are non mag and some of the legs for the wind screen. Looks like they were almost cobbled together as there seems to be no rime or reason.
I have seen some of the earlier 1950 dated M50 stoves that were total rust buckets. Most of the later dated stoves seem to have very little rust.
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Re: M1950 questions

#26

Post by TunkTop »

Well, this has been interesting. After six weeks of frustration, I was finally able to get the pump barrel out of the fount.
Repeated applications of 50/50 Acetone and AT fluid, Kroil, and PB Blaster were fruitless. Careful application of heat did nothing. 50 lbs of air pressure in the burner hole was uneventful.
A suggestion from macwacs that there was likely corrosion in the fount tube was right on the mark. I filled the fount with Evapo Rust and put it over a dowel in my vice so the tube was submerged and waited.
CDBE63C8-DC80-4F00-A6C6-70369D192986.jpeg
After a week, I made a rubber expansion plug that would just fit in the pump barrel and added heavy weight with a hole through it to make a rudimentary slip hammer.
A9C6616B-53FF-4302-A8B5-65EED91C0B5F.jpeg
Once it started to move, judicious lube and working it back and forth got it out I damaged. The fount tube was pretty crusty with semi dissolved rust, but it cleaned up pretty nicely with emery cloth and scotch brite pads.
0843B2DE-2FAE-4696-A0C6-DB35F992D98C.jpeg
Thanks macwacs for for getting me on the right track!
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Re: M1950 questions

#27

Post by stoves1234 »

Wow-expansion plug, slide hammer-good idea! Flame shots required when you get it running.
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Re: M1950 questions

#28

Post by TunkTop »

Back together and fired up for the very first time!
310D9C93-D8D0-4852-B247-33EFE34763FF.jpeg
This was totally a team effort. Once again the crew on this forum turned a bunch of parts into a functioning stove. Thanks everyone!

Well, I have to go now because it is a personal quirk of mine that a restoration is not complete until a pot has been brewed on it. :D
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Re: M1950 questions

#29

Post by Gunhippie »

Enjoy your cuppa'! You've earned it.
It's priceless until someone puts a price on it.
Walk a mile in a man's shoes before you criticize him--then you're a mile away, and he has no shoes.
Texan's last words: "Y'all--hold my beer--I wanta' try sumptin'."
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Re: M1950 questions

#30

Post by macwacs »

Glad to have been of assistance. I have seen several pump tubes ruined by not removing the interior fouling first. Use and enjoy my friend.
RMW
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