Wednesday, March 2, 2011

Stove of the Week: MSR XGK II (Pre-Shaker Jet)

Great strides are made by great men.  In the world of modern pack stoves, one man stands out:  Mr. Larry Penberthy, founder of MSR. Larry Penberthy (March 11, 1916 - November 24, 2001) was an iconoclastic genius. 

Behold his creation:  what is now known as the MSR XGK stove:

Penberthy observed that one of the leading contributers to the cold weather killer, hypothermia, was dehydration.  Why were mountaineers getting dehydrated?  When all the world around you is cold, hard, and white, water is tough to come by.  The stoves of the day were largely tank mounted brass stoves, beautiful works of art still cherished to this day, but hardly light.  Many mountaineers, unwilling to pack their excessive weight faced dehydration instead, risking hypothermia.  Penberthy, a mountaineer himself and a first rate engineer, set out to design a stove.  He noticed that climbers of the day tended to carry spare fuel in Sigg aluminum fuel bottles.  Why, he reasoned, should people carry in effect two fuel tanks (one as part of the stove and one in the form of the Sigg bottle)?  He designed a pump that would screw into a Sigg fuel bottle, turning the bottle into a pressurized fuel tank capable of delivering fuel to a burner.  His stove, now no longer sitting on top of a fuel tank was lower to the ground, making it relatively stable and bringing it down out of the wind.  He then added a sheet of approximately 6" x 31" heavy aluminum foil as a windscreen.  On stoves where the tank was directly attached to the burner, a windscreen of Penberthy's design could trap too much heat and cause the fuel tank to explode.  On this new type of stove where the fuel tank was separate, a windscreen could be safely used.  Today, we look at things like a fuel bottle used as a fuel tank with the fuel well away from the burner and an aluminum windscreen as obvious.  Let us not forget that it took a visionary like Penberthy to come up with something so simple and yet so effective.

He also made his stove field maintainable:  The jet could be unscrewed for cleaning or replacement with a simple slot head screwdriver.  He added a cable that ran down the fuel line that could be used to scour out carbon deposits.  Penberthy made the stove solid as though his life depended on it -- for in fact his life did.  Penberthy climbed using his own inventions.  Penberthy designed not only his brilliantly innovative stove but also ice axes, helmets, and other climbing equipment.  When taken as a body of work, his genius is clearly seen.

Penberthy's stove design revolutionized climbing stoves, providing a relatively light weight, relatively wind proof, effective stove, a stove that climbers were not only willing but glad to carry.  Sadly perhaps, Mr. Penberthy's design may have contributed to the demise of the classic brass pack stove.  Penberthy's first production stove was the Model 9.  The Model 9 was a white gasoline only stove.  The Model 9 was then joined by the "MF," a multi-fuel stove.  Later, the Model 9 became the G (gasoline) stove, and the MF became the GK (gasoline/kerosene) stove.  Later still, the G and GK stoves were merged into one stove, the XGK.  It is by the moniker "XGK" that this line of stoves is generally known.  The XGK was supplanted by a somewhat redesigned XGK II which dropped the wire coil around the generator, removed the surge dampener, eliminated the flint ignition, and did away with the aluminum cup which used to come with the XGK.  The XGK II had three versions:  the first without a shaker jet, the second with a self cleaning "shaker" jet, and the third also with a shaker jet, a redesigned spreader plate, and a new "X" type of removable pot support. Eventually, the XGK II was replaced by today's XGK EX.

To this day, many a mountaineer swears by the XGK.  In cold weather, the efficient, powerful XGK is the snow melting stove of choice.  Recently, I noted with interest some photos on a polar explorer's web page.  The stove in the photos?  The MSR XGK. A year or so ago, I had an MSR XGK on the table in front of me at a Sierra Club function.  One of the members, a serious climber, remarked, "on Aconcagua, that was the only stove that worked."  Aconcagua (22,841 ft/6962 m) is the highest point in the Western Hemisphere. 
It is only fitting that in my series on winter capable stoves that the XGK be included.

This week's stove is the first of the XGK II's, the pre-shaker jet XGK II.

The pre-shaker jet XGK II originally came in a long black bag, shown here beside a more modern XGK II bag:

The bag was marked with the old "Matterhorn" MSR logo.

The stove came with the following contents:  The stove itself, a third generation gray and black pump, a windscreen, a heat reflector, an alcohol squirter bottle, a stuff sack (the bag in the photo is not the original XGK II type bag), instructions, and a small parts and maintenance kit.

A closer look at the contents
This interesting insert came with this particular XGK II, an early model XGK II evidently produced shortly after the cutover from the XGK to the XGK II.  This insert was intended to supplement the regular instructions -- which were the instructions for the original XGK.

The original instructions say some fascinating things.  Take number "6" below.  It says "Use kerosene as a fuel and provide adequate ventilation..."  The rest has been crossed out by hand with a black marker, but it's still readable and says, "should weather conditions necessitate the use of the stove inside a tent."  There you have it, folks, the "elephant in the living room."  Everyone knows that in really bad weather that you have to cook inside your tent, yet every modern stove manufacturer prints warnings in big letters to never cook inside a tent.  Things were different back then.  They leveled with you instead of hiding behind their lawyers.

Nowadays, MSR says "only use MSR bottles with MSR stoves."  That's a pretty funny thing to hear from MSR when you consider that MSR stoves were designed to work with Sigg brand bottles!  Indeed, the thread of every MSR pump and every MSR bottle is based on Sigg's threads.  Again, in the old days, MSR was a lot straighter with you.  These instructions, though hand crossed out, say "Exercise care in the selection and use of other manufacturers bottles."

Next, let's look at the pump.  This is MSR's third generation of pumps, the gray and black pump.  The very first pumps were white, the second generation, of which there were many variants, was yellow and black.

I won't go into all the details here, but basically the gray and black pump was a step backwards for MSR.  The gray and black pump is inferior in every way except for the re-designed air supply tube which is an improvement.  MSR took a step backwards?  What happened?  Well, in 1980, Larry Penberthy sold MSR to REI.  REI started making changes to cut costs.  They redesigned the XGK, eliminating several costly items like the surge dampener, the flint ignition, the protective aluminum cup, and the coil on the generator.  They also completely redesigned the pump, coming up with the gray and black pump pictured above, a pump far less robust but much cheaper to produce.  MSR then gained a reputation for having crappy, unreliable pumps.  The next two iterations (red and gray, red and aquamarine) of MSR pumps were no better than the gray and black and possibly were worse.  Fortunately for stove users, MSR came out with their current "duraseal" pump some time around 2005, a much improved pump.  Is the duraseal as good as the old yellow and black pumps?  Perhaps, but the jury is still out on that.

Well, let's have a look at the stove itself, shall we?
Note the rigid fuel line.  The fuel line, when locked into the fuel tank (via the pump), forms part of the support of the stove.  The XGK is actually a fairly stable stove despite its relatively small base.  In the photo above, you will note the aluminum foil collar around the stove.  This is the heat reflector and is designed to reflect heat up to the pot, maximizing efficiency.  Note also the large diameter of the generator (pre heat loop).  The XGK can handle some pretty crude fuels.  Indeed, many a mountaineer has benefited greatly from the XGK's rugged, robust design when burning rather questionable third world kerosene while high on a remote mountain.

Included with this stove are the below shown parts:  a wrench/tool, a pricker for cleaning the jet, a "sintered" brass fuel filter, and a spare jet.

Note the letters stamped into the jet, an "X" and a "K".  The "X" indicates that this is an XGK jet (as opposed to any of MSR's other stoves), and the "K" indicates that this is the jet for kerosene.  The jet that comes installed with the stove is typically marked "X" and "G" indicating that the factory installed jet is the XGK jet for gasoline.  The "G" jet should be used with Coleman fuel, true white gasoline, automotive gasoline, naptha, panel wipe, "environmental" gasoline (e.g. Aspen 4T), aviation gasoline etc.  The "K" jet should be used with kerosene, diesel, jet fuel, Kleen Heet, etc.  Note:  Coleman type fuel and kerosene will always be the best fuels for pretty much any petroleum based liquid fueled stove.  In a pinch, you can burn some of these other fuels, but your stove will not run as well, will clog more (hope you know how to field maintain your stove), and may produce some pretty noxious emissions.  Use "alternate" fuels (fuels other than Coleman type fuel and kerosene) only when you have to.

Also included was this small squeeze bottle, intended to be used for alcohol for priming.
Alcohol is the traditional means of priming stoves that run on petroleum based liquid fuels.  It burns more cleanly (especially when compared to the nasty business of priming with kerosene), is easier to control the amount dispensed, and is far less prone to producing a fireball that can shoot up from the stove. Fireballs are particularly common when priming with gasoline type fuels.  Oddly, MSR no longer encourages priming with alcohol.

Here, the stove is set up and ready for use.  I've removed the windscreen for visibility's sake.

Here, the windscreen has been emplaced.

Time to fire her up and put the kettle on!

The XGK passes the "tea test" with ease.

Let's have a look at the flames, shall we?  The XGK is known for it's power and rightfully so.

  But note this shot here:
Now, I won't call that a simmering flame, well, not exactly, but that is a pretty low flame.  It took some fiddling, but I was able to get some relatively low flames out of an XGK.  I and other owners of older XGK's have noted that older XGK's are capable of a lower flame than newer XGK's.  Why might this be?  The pre-shaker jet XGK II and the shaker jet XGK II are so very similar; shouldn't the flames be the same?  I honestly don't know why the flames are different, but possibly there's something about having more empty space inside the jet that makes simmering more difficult -- empty space that has to be there in order for the shaker to, well, shake.  That's my theory anyway.  I notice the same thing on my pre-shaker jet MSR Whisperlite, that it simmers better than any shaker-jet Whisperlite.  This isn't isolated.  I've used multiple pre-shaker jet MSR stoves.  Every pre-shaker jet MSR stove that I've used has consistently simmered better than any shaker jet MSR stove that I've used.

Well, there you have it, the mountaineer's friend, the ultimate snow melting machine, the MSR XGK.

Thank you for joining me on another adventure in stoving,


What's good about it?

What's bad about it?
Expensive (The XGK line in general -- although used ones can be a true bargain)
Difficult to simmer (although pre-shaker jet models simmer better)
The swiveling wire pot supports tend to move around too much during use.  (Newer models have done away with the old swiveling pot supports)
The rigid fuel line, while adding significant stability, is a bit hard to pack  (Pretty minor issue)

Overall, highly recommended.


  1. Hi Jim, cracking review, for a stove I use and love. Would agree with almost all your comments - certainly simmering takes some effort to learn to control the flame but is possible with effort. Would you mind if I linked to your review and possibly use one picture from your blog to illustrate it on my own blog www.solentseakayaking.co.uk

  2. Which part did you not agree with. ;)

    I responded to your comment more formally via your contact page. HJ

  3. Really the only thing I have noticed 'slightly' different to your findings is ability to simmer with pre vs shaker models - it has seemed very similar to me. However, this is based on limited experience of pre-shaker stoves and I would defer to your more rounded experience on this :-)

  4. I have acquired an old XGK stove, one with the heat diffuser spring and yellow pump. It seems to work fine, but I'll probably take it apart and clean it. I only have the white gas jet. do you know if the current kerosene jets will work with this old stove?

    It appears that there was an absorbent pad under the burner for the priming fuel. It's pretty well worn out. I was using gelled ethanol for priming and it seems to work pretty well, but that was on white gas. I've downloaded the current model instructions from MSR, but I'm sure that there are some differences in the older stoves. I don't want to tear it up trying to take it apart, but I would like to try to restore it as much as possible.

  5. Bill,

    I'm pretty sure a modern priming pad from an XGK II or XGK EX would fit an older XGK.

    The older XGK's though had a different jet than the current stoves do. The current stoves all have shaker needle jets. You could call MSR and see what they have in stock, but modern jets will not fit an old pre-shaker jet XGK.


  6. I'm not sure how to get the priming pad on. My XGK has what appears to be a bakelite pad riveted to the bottom of the brass stove surround. I think that the priming pad is held on by the burner and I don't think that I can get the burner off without drilling out the rivets. I don't want to do that unless I have to. I could use a modern pad by splitting it and inserting it under the burner. I need to spend some more time looking at the stove. I doubt that they would have built one that wouldn't allow the priming pad to be replaced.

    I need to take the jet out and have a look at it. If I new what size hole it needed, I could probably make one. As it is, I'm not going to alter the one that I have. I'll keep an eye out for another old stove.

    Do you have a good source for parts or would you deal directly with MSR?


  7. Bill,

    1. Unscrew and remove the striker rod assembly.
    2. Rotate the burner assembly by gripping the fuel line and moving the fuel line into the space formerly occupied by the striker. The stove is old, so don't force things.
    3. You should now be able to pull the burner upwards out of the housing. I don't think you can fully remove it because of the aluminum block and catch arm at the far end of the fuel line, but you should be able to get it up far enough to get a replacement priming pad in.

    For parts, MSR has some, but frankly they haven't got the really old stuff. I usually cruise eBay looking for old parts kits or, hate to say it, cannibalize other stoves.

    Creating your own jet can be done if you have a lathe and proper tools. The aperture size is fairly critical. I don't know the aperture size of the "K" jet for an old XGK.

    My Omnifuel comes with jets with three different sized apertures, one jet for each of the three general classes of fuel: gas (0.45mm), gasoline (0.37mm), and kerosene (0.28mm).


  8. I figured out how to get the burner out and it was just as you described. I should easily be able to use the modern priming pads. I have the lathe and tools to make jets, but the smallest hole that I can drill is about.34mm, which is probably too large. There are other techniques for making very small holes, but I think that I will keep my eye out for an original jet. The most critical part of the jet is the sealing surface that keeps fuel from leaking around the jet. This may be be fairly difficult to do. The simplest thing is to take an old jet and braze the hole shut, then re-drill it.


  9. Bill,

    Excellent. Glad to hear you were able to get it apart.

    The other thing you can do to close up the jet is to "peen" it (as with a ball peen hammer). I haven't tried this, but some guys over at CCS have done this successfully.


  10. I could take a small pin punch and use it to close the hole. This would probably work better than trying to peen the jet, since the orifice is at the bottom of a screw driver slot. A small, say 1/16", pin punch held directly over the orifice and hammered in to the metal would cause the orifice diameter to shrink. It's a bit tricky, but should work. I won't try it on the stove that I have, since I only have the one jet. I took the jet out and can see that it seals on a taper at the top of the threads. This type shouldn't be too difficult to make, since the length of thread isn't critical. My jet has a screen in it and appears to have had a porous metal filter pressed in to the base of the jet. The filter is there, but was loose in the burner base. There appeared to be some carbon buildup on the filter. I'm ambivalent about these filters at the jet because of the carbon buildup and the difficulty of cleaning it out. A screen is OK, as it just prevents large particles from clogging the orifice.

  11. From what I see on CCS, my stove is probably a GK.

  12. Oh, you lucky dog. I've been wanting one of those. Did you post pics on CCS?


  13. I haven't taken any, yet. I'll try to before too long. What I thought was a loose filter appears to be the surge damper.

  14. That does sound like the surge dampener not a filter. I'm not aware of a filter in any of the XGK line of stoves.


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  16. Parts...I need parts....help? I have a 26 year old XGK, the base is completely shot, as is the square of fabric that doesn't burn. Other than that, I have held it together, but need parts....

    1. MSR no longer stocks parts for a stove that old. Your best bet is probably eBay or a forum like Classic Camp Stoves. I've gotten a lot of parts by purchasing a similar stove and then canibalizing one to get the other functioning. I wish I could point you to some "gold mine" with all the old MSR parts you'll ever need, but unfortunately there is no such thing. There are parts out there if you're persistent. Good luck!