I do like to start with a flame shot: The MSR G & GK stoves were manufactured between September 1977 and October 1981. This particular stove was bought in the U.K. in early 1980 and although it could have been manufactured in 1980 it is more likely that the UK importer (in this case Field & Trek) brought it into the U.K. in 1979 or earlier. Not that it matters. The climber from whom I obtained this stove told me: “I seem to recall the first time I used the stove in anger was at the Blumisalp Hut above Kandersteg .The reason I remember it so well is because there was a group of us cooking outside the hut (couldn't afford hut food in those days) when a helicopter landed nearby, all the stoves were blown out except my MSR. I continued to use the stove in Austria, France & Switzerland as well as all over the UK up until 1996.” I have posted the instruction booklet that came with this stove in the Stove Reference Library here: https://classiccampstoves.com/threads/19906 I have also posted photos and instructions for the maintenance kit (Comprehensive) in the Stove Reference Library here: https://classiccampstoves.com/threads/20231 And the basic one the Stove Reference Library here: https://classiccampstoves.com/threads/20230 A photo of the stove can be seen below: Before continuing with the description of the GK I am going to step back and go to the origins of this stove: When the stove designer, Larry Penberthy designed the original, he had in mind that the stove could run on various fuels. We know this because it can be found in the historical record. However, the first production model, the model 9, was designed for the use of gasoline fuel only. one can see photographs of the Model 9 in the Stove Reference Gallery here: https://classiccampstoves.com/threads/18262 The reason for the model 9 running only on gasoline was probably due to the fact that these stoves were available to Americans where “white gas” was and still is freely available from various stores. In the seventies and eighties North America was probably the only pace on the planet where this fuel was freely available. Elsewhere, then, and to this day, Kerosene was and still is the most easily available fuel. if MSR wanted to increase its sales beyond America and for American climbers who wanted to climb outwith the U.S.A. with their stoves then the stove had to be capable of running on Kerosene. In 1975, in response to many customers requesting multi-fuel capability the MSR Model MF was introduced. (Source Mountain Safety Research Newsletter, March 1975). Photographs of the MSR MF can be found in the Stove Reference Gallery here: https://classiccampstoves.com/posts/169588 The Model MF, introduced in 1975 was manufactured until August 1977 when production ceased and the Model GK was introduced. All the early models, The model 9, G, MF and GK had some parts in common with those described within the 1973 patent application and all these were common to these stoves until Penberthy sold MSR to REI. On Acquisition of MSR by REI the following items were absent from the subsequent model, the XGK: 1. The jets were no longer fitted with what Penberthy, in his patent application described: “ A more important aspect of the present invention” that was the 0.005” dia screen within the jet which was to avoid clogging of the jet. The screen diameter, which was less than the jet orifice diameter was novel. 2. The burner was no longer fitted with the sintered brass “surge” filter. In the patent this is referred to as “a solid metal plug with helical threads defining grooves …” The purpose of which was “ to insure that no liquid fuel is made to flow through the helical passageway formed by the metal plug and the adjacent walls of the elbow. Plug MAY (my emphasis) comprise a screw threaded metal rod with a light press in the passage way of the elbow.” That the production models (9, G, MF and GK) had a sintered brass “plug” matters not as Penberthy, on Page 6, last paragraph, column 5, of Penberthy’s patent application (United States Patent 3,3829, 278. which can be found at the end of this post as a pdf attachment in the Stove Reference Library, subsection Patents: https://classiccampstoves.com/threads/20584 says “ The invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiment is therefore to be considered in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.” 3. The Shielding coil, whose purpose, according to the instructions which can be found in my post in the Stove Reference Library here: https://classiccampstoves.com/threads/ And in MarbleCreek’s post, also in the Stove Reference Library, here: https://classiccampstoves.com/posts/144542 “Shielding Coil — Model GK. The wire coil on the fuel tube across the burner is there to decrease the temperature of the fuel tube by deflecting the flame from directly touching the fuel tube.” 4. The sparkers unit. This was part of the original design and appears in patent No 3,900,281 which is a continuation of patent No 3829278 previously referred to above and can be found in pdf format attached to my post in the Stove Reference Library here: https://classiccampstoves.com/threads/19570 The next model, the XGK also had a pump change, something I will not dwell on here but will touch on later in this post. I will now continue with the description of the GK: In the photo below one can see the burner unit, and the fuel tube with the thick steel shielding coil attached. Careful observation will show that the K jet is installed. One can also see the sparker unit within the Aluminium cup enclosure. This photo shows the sparker unit attached to the enclosure. Photos of a pristine sparker unit can be found in my post in the Stove Reference Library here: https://classiccampstoves.com/threads/20235 The catch arm, as illustrated below, is identical to the model 9, MF and G. It is exactly like the catch arm as shown in Fig 2. in patent application No 3900281 shown in the attachment in this post: https://classiccampstoves.com/posts/201099 and is shown here: My photo of the GK catch arm is shown here: The catch arm changed with models as can seen in the next photo – the nearest to camera is from the GK, the middle one is from a XGK II Expedition Stove shown in this post: https://classiccampstoves.com/threads/20449 And the final one is from a XGK II shown in this post: https://classiccampstoves.com/threads/19881 The Aluminum block is not date coded on this GK, in fact, I am unaware of any date coding until 1981 when the company was taken into REI ownership. The practice of date coding the Aluminium alignment block was continued under the ownership of Cascade Designs. The jet, with its press fit screen of only 0.005” diameter was, according to Penberthy’s patent, one of the most important aspects as it avoids clogging and obviates the need for a cleaning needle. The patent goes in to quite some depth in this issue and the interested reader will find it in the attachment here: https://classiccampstoves.com/threads/20584 The sintered brass “Purge Filters”, referred to earlier in the text are illustrated below: Among the accessories supplied with the model 9, MF, G and GK was a aluminium cup. The climber I obtained this stove from used it to protect the stove as can be seen in this photo: The bottom of the enclosure holding the burner is a synthetic material which appears to have flame retardant properties. Later models were made of Aluminium. Photo below: The model 9, MF, G & GK were supplied with a yellow pump. This was an all plastic pump with the exception of the pump rod which was aluminium. The yellow pump came in several versions of which I have examples. This stove came with this pump: I do not use old MSR pumps due to their flawed design, particularly with the Aluminium valve screwing directly into plastic. All MSR pumps prior to the Duraseal pump suffered from this anomaly. MSR suffered pumps problems right from the very start of production, 539 pumps were recalled in early 1974 of pumps manufactured between December 28 1973 and January 21st 1974…”one pump with threads on the small side were matched with bottle threads on the large size whereon fuel leaked out . This would have presented a substantial fuel hazard” Source: MSR Abstracts from Newsletters and press releases as reported in Stoves for Mountaineering see my post in the Stove Reference Library here: https://classiccampstoves.com/posts/114595 This photo illustrates the Aluminium valve screwing directly into plastic: The pump that replaced the yellow pump, the grey bodied pump with the black plunger is another example: Fortunately, MSR now supply an excellent pump with a brass sleeve and the valve screws into that, not into plastic as I have illustrated here: I do find it quite bizarre that considering that the design of the original stove was innovative, imaginative and built for durability – that the pumps were essentially cheap plastic moulding. I can but assume that the cost of a metal pump would have made the total cost of stove, as sold to the public, prohibitively expensive for the US market at that time: In 1973 the cost of a SVEA 123 was $12, an Optimus 80 and a Primus 71L $11, Optimus 8R $13, Optimus 111B $20, Optimus 00L and Primus 210 both $15 and the Primus 100 $10. LPG gas stoves were as follows: Bluet S-200 $8 and The Gerry Mini-Stove $10. The Primus Ranger with its tripod legs was a mere $6. Alcohol stoves were virtually absent except for a very basic one found in some mountain shops and the Turing Turm at $13 if you could find one. Source Backpacking One step at a Time by Harvey Manning Vintage Books 1973 and by personal observation as I spent much time in the Western USA and Western Canada at that time. In the final analysis, cheap plastic pumps have to be regarded as a “consumable”. I’ll finish with another flame photo – one of this GK with a Bernie Dawg Midi-Cap replacing the flame plate which makes this stove run virtually silent.
Good morning Rob a fantastic documented break down of the MSR GK the flame shots are outsanding as all ways,the MSR GK sure is a fantastic perfomer looking at the pics burning with a perfect atmospheric blue flame and bright cherry red flame spreader and burner basket,i can never seem to take a pic of a flame shot with your quality
Rob, I bow to you for: 1) All of your experience & knowledge. 2) Your sharing of that knowledge with us here. Thank you very much. I have a GK coming in the mail. The seller said his father had it issued for survival in the early 1980's. The note with the stove says it was test fired Dec 21, 1981 (??). The catch arm is different from the catch arm on the GK in your post. I will know more when I get it in 3-5 more days. Ken
Hi Ken, It looks hardly used,going by what I can make out ion that small photo - the windshield and heat reflector in particular. Looks like you got the original packaging too which is good if you are a collector. The date is about right...Although MSR stated that the the GK was manufactured between September 1977 and October 1981 obviously they would have quite a few stoves that would have been produced before starting the next model the XGK. There was an overlap for all the models - the nature of production/sales. When you do get your stove, think about taking good close up photos and post then in the Stove Reference Gallery. Cheers, Rob
Hi Ken, I looked that GK stove up under completed listings and essentially you have a new stove. It looks unused to me. As in many production processes (and certainly for stoves over the last century – do look at Bryan Millers History of both the Optimus & Primus 96 for example) there are items made and assembled separately. The catch arm on the stove you bought is the one that MSR fitted to the XGK. It is difficult to make out the colour of the enclosure but I think it is the “gold” one. As you have the maintenance kits coming with it that is good as you will have the jets, surge filters, spare springs for the sparker etc. I’d advise putting the pump to one side and use only the Duraseal pump. Cheers, Rob
Yes, about the yellow pump, I have read often it can break if the adjustment screw is tightened too much. I will check my other pumps to ensure they are the latest, and buy one if need be. Ken
I forgot to mention that for those people that have bought the GK stove second hand and do not have access to the jets supplied to this stove there is a simple solution: Just fit a MSR XGK II jet which are still available from good mountain climbing shops. The part number is MSR 419250 for the G jet and MSR 419251 The thread is exactly the same. In the top row in the photo below are the original jets and the bottom row are the jets from a XGK II.
The tape came off very nicely. I put very hot water in the bottle, waited a few, then peeled it easily. I used white gas to clean it off. The only problem the tape caused is the price label, the price is gone. The MSR label on the Sigg bottle is unchanged from the tape. I didn't peel the tape off the box, I cut it off where it left the box. Ken (Got pictures to post, gonna make a new post)
"Fortunately, MSR now supply an excellent pump with a brass sleeve and the valve screws into that, not into plastic as I have illustrated here..." The valve does still screw into plastic. I do understand what you where meaning, and yes this pump is a great improvement on the old style. The dragonfly pump is better again, with its sprung poppet to stop leaks. PDF MSR PUMP SPECS
Good Morning, Snowgoose, I just re-read your excellent report here, Rob, and must tell you, again, how much I appreciate the work, effort, time, and experience that went into your creating and posting it! This is, simply put, one of the best informational reports I've yet seen in the MSR X-GK family!! As you know, this stove has a firm and irreplaceable spot in my heart, like no other stove. So, I offer my thanks for you directly from that very heart, Rob!! Well done, and absolutely first cabin!!!! Thanks, again, and God Bless! Every Good Wish, Doc (proud as punch of the work that you created here!)
