New member here. I discovered this site while trying to figure out what to with my 1970s backpacking equipment which includes an MSR Model 9 stove. On CCS, I found lots of discussions about early MSR stoves and history of the various versions of burners and pumps. I joined CCS because I hope to add a little to the knowledge of the Model 9 before I sell it here or elsewhere. (My wife wants me to tidy up the stuff I don’t use and our three girls and their spouses don’t want it.) In my writings here, I will try to be clear to say “I think” or “I suspect” if I don’t know for sure. I’m going to go into detail because I don’t know what might help in furthering understanding. Please bear with me if I don’t use the correct names for some of the parts. I pre-ordered my stove when they first came out. It replaced a heavier stove (bought about 1970 or 1971) that I passed on to my brother. MSR Items I have that I know came with the original order. Unfortunately I don’t know the date. Model 9 Burner, scalloped burner bell, short support arms, slender sparker knob, 2 O rings on catch, Masonite base, aluminum cup cover, MSR sticker on fuel line White Pump, square regulator knob with pointer line (no logo), external check valve (no air supply tube) Wind Screen Heat Reflector Major Point I think this adds to the Model 9 history: I pre-ordered a stove directly from MSR and received a white pump with square regulator knob and no air supply tube. Minor Point that may add to the history: The fuel line on my stove has an MSR logo sticker wrapped around it. I think it came that way as I don’t remember putting it on. I was not going to mention this but there is a picture in post MSR N. 9 - Up Close and Personal by idahostoveguy that shows what looks like a residue on the fuel line that might have come from a sticker. Hopefully someone can shed some light on this MSR No. 9 - Up Close and Personal Other MSR Items I have but I don’t know when or how I got them. MSR may have sent them since I was on their mailing list at the time or I might have picked them up from a store. MSR Stove Spare Parts Kit, undated, no catalog number, all contents present except for Package of Flints which I think I removed because they were turning to powder and dirtying the bag and Instructions sheet. MSR Information Sheet #10 How to Use Jet Cleaning Wire, undated, no catalog number, (I think this sheet came with Spare Parts Kit.) MSR Yellow Pump, round knob with MSR logo, MSR Stove Model 9 tag, cotter pins, air supply tube broken off with tip still in base and most of the other broken pieces found at the bottom of the bag SIGG Items I have but I don’t know when or how I got them. I think I got the small bottle and pour spout when I got my first stove in 1970 or 1971, probably from REI. SIGG .6 quart Fuel Bottle, metal cap SIGG 1 quart Fuel Bottle, plastic cap, bottle has two red labels with white dots encircling the body SIGG Pour Spout, spout appears to be a metal tube that comes vertically out of the top, touching the handle, and going past it about 1/4 inch I used the stove pretty often until about 1977 and then less until the last trip I remember in October 1982 to the Pecos Wilderness North east of Santa Fe. After getting married, I had a 3 year overseas assignment starting in early 1983. All camping equipment went into storage (empty fuel bottles). We had one girl when we came back and then added two more over the next few years and did do a little car camping (Coleman two burner). I always used Coleman Fuel with the MSR stove and never stored the white pump in a fuel tank. The stove never leaked. I never replaced any of the o rings on pumps or bottles. I never used the yellow pump as I never had any issues with the white pump. The yellow pump air supply tube disintegrated at some point. I don’t see any obvious cracks in the white pump. If you pump it, it makes a pumping noise. I have not tried to test it. My small SIGG bottle’s cap is frozen shut and I do not want to try to force it. The large SIGG bottle has the thread insert (I think). The yellow pump does not make a pumping noise. I am going to try to include several pictures of the stove with many closeups of the white pump. I will try to respond to any questions. I noticed in one of the white pump pictures that there were concentric rings on the face of the knob. The top part of the body of the white pump has some sort of texturing or tool marking visible. Addition to Post of July 24, 2020 After my posts in July, I was still curious about several details of my stove compared to other Models 9s. I became a Subscriber and tried to read everything I could find in CCS and elsewhere, about early MSR stoves. I soon realized that I had more to contribute to the Model 9 story. I asked @Spiritburner about where to add additional information and he volunteered to edit it into my original post. (Thanks @Spiritburner.) The remainder of this post contains these parts: Sparker Knobs and Pump Tags – I posted this July 27, 2020 in reply to my first post; copied here (with minor editing) to try to keep the discussion coherent. and new discussion posted November, 2020 Pump Tags Update Model 9 Details and Other MSR Items Burner Details Pump Issues and Testing Flame Shots!!! Sparker Knobs and Pump Tags All, @hikerduane, @Doc Mark, @oddball, @Pinky, Since my post, I received several nice replies and PMs. Thanks all! I have two new points I would like to share, one about the sparker knob and the other about the MSR Model 9 tag. While going through the three storage boxes (two 10 gallon and one 18 gallon), that my wife had kindly brought downstairs from the closet and put in front of me to work on, I found my original MSR Model 9 tag which is not identical to the one on my yellow pump. When I compared the two tags, reading them word for word, I was surprised about the differences. There was also one nagging thing bothering me when I originally posted, because I hadn’t had time to research it - my Model 9 sparker knob is slender and pics I saw of Model 9s were fatter, even though I saw some later models with slender knobs. Yesterday I found an old post discussing this, so I thought I would discuss this too. I don’t know if there are other posts that I have not seen that address these points. I’m sure someone in the CCS community “knows”. Point on sparker knob: I pre-ordered a stove directly from MSR and received a Model 9 burner with a slender sparker knob. It is not a replacement. Point(s) on Model 9 Tag There are differences between model 9 tags, at least one is significant. Yellow pump: Text includes: “Do not open valve more than three turns...” Reverse side has, what I think, is the standard warning text Reinforcement of hole is a circle The tag that I just found yesterday, that must have come with my original stove: Text includes: “Do not open valve more than two turns...” Reverse side has no text Reinforcement of hole is circular with bottom cutoff and top extended The difference between two and three turns is significant. Discussion and pics: Sparker Knob In this thread: Different MSR model 9's & my PW 4 The stove on the left has a fatter knob and the stove on the right a slender knob (appears to be like mine). And in a reply I can confirm that at least one Model 9 came with a slender sparker knob. Model 9 Tag Here are pics of my two tags Fronts Backs In searching the forum I found some tags that were different to the one I just found. I did not do an exhaustive search, but I looked at all I could easily find. Here is a “three turns”: In this post he made for @hikerduane: MSR #9 - A Rare Find Tag says “three turns”, hole reinforcement is circular. Back not shown. This tag is similar to the one on my yellow pump. Here is a “two turns”: In this thread, MSR Model #9 @Pinky shows his Model 9 and includes: Tag says “two turns”, hole reinforcement is not circular and warning text is on back. This is similar to my original tag except my back has no text. So I have shown three different early MSR Model 9 tags. I don’t know the significance of the two turns vs three turns. Hope you get something out of these details. (End of original post July 27, 2020, start of new material November 20, 2020.) Pump Tags Update When I first looked at my pump tags, I compared every word on my newer tag to my original tag and found that two turns on the original tag had been changed to three turns on the newer tag. A few weeks later, I realized that the newer tag was missing an entire statement from the original tag: Store the pump outside the fuel bottle when not in use. Some tags in pictures posted to CCS have the “Store … outside ...” statement blacked out. See for example MSR Model 9 ~ 9A posted by @anfeng Aug 22, 2020. Picture at this Link. and MSR Model #9 posted by @kjhriverrat Mar 20, 2020 I think the reason for the “Store … outside” tag change was explained by MSR. In 1975, Off Belay published a booklet Stoves for Mountaineering (Off Belay – 1975) (posted by @SNOWGOOSE). Page 27 of the booklet contains Abstracts from MSR Newsletters and Press Releases - March 1974 to March 1975. Many of the abstracts have been commented on in CCS. Click image to view the full page of abstracts, large size. The first part of one abstract, March 1975 - “How is the MSR Stove Doing”, says: As far as I can tell, the first two problems have not been referred to in CCS. This documents the switch from the gray bottle gasket to the black Viton O-ring and explains removal of the caution on later pump tags and instructions to Store the pump outside the fuel bottle when not in use. This is also a plausible explanation for this sentence being blacked out on some pump tags. The gaskets on my white pump, my two Sigg bottles and the separate pouring cap are all gray bottle gaskets. The metal cap Sigg bottle was stuck shut and the gasket was very hardened. I spent about 2 hours cutting away the edges of the gasket with a utility knife until I was finally able to open the bottle. I still have the two largest pieces. This documents the switch from brass bushings to Delrin bushings. My white pump has a brass bushing. I did not receive any notice from MSR, probably because I moved apartments before the fall semester of 1973 and then a move to another state in the summer of 1974. Model 9 Details and Other MSR Items MSR Logo Sticker, Housing I found a picture on the internet of a model 9 with an MSR logo sticker on the fuel tube. Here is my recreation of that picture. I discovered the same picture in The Stove Reference Library > Articles > Manufactures > MSR (Mountain Safety Research), posted by @Spiritburner. Here is a snippet of the article and the picture for comparison. The MSR logo sticker on the fuel tube is like the one on my stove except the one here shows the MSR mountain pointing from back to front and my sticker has the mountain pointing from front to back. The logo sticker has a blue colored design on a transparent background. The main differences you can see in these pictures are the angles between the fuel tube and sparker and the slender vs stubby sparker. Here is a picture of my stove’s housing showing three openings in this side: a large air opening, a smaller opening for the fuel tube, and a second smaller opening for the sparker. This is the only Model 9 I have seen, so far, that has three separate holes in that quadrant of the housing. The fuel tube angles down slightly as it comes out of the housing. If you zoom in on the fuel tube at the housing, you can see small parallel ridges along the fuel tube. In another thread, @Spiritburner posted some closeup pictures the stove in the MSR article: This second picture shows the fuel tube attaches to the burner near the center of the large air opening. To the right of the large opening, is a small connected opening. and then further to the right, the sparker is attached through another small connected opening (or a separate small opening, it is hard to tell from the picture). Most model 9s that have housing pictures in CCS show connected openings like this, but the fuel tubes are in the smaller opening to the left of the sparker. Note this fuel tube looks the same all the way into the burner – no parallel lines. The third picture shows a pump tag that matches my original pump tag. The catch wire has 2 O-rings behind a metal retainer like my stove. The similarities and differences between these two stoves led me to explore Model 9s further. Another Model 9 with MSR logo sticker and fuel tube in the large opening I found pictures of another Model 9 that is very similar to the one posted by @Spiritburner. The pictures were in a Japanese blog posted July 13, 2009. Similarities include positioning of the MSR logo sticker on the fuel tube, white pump, square control valve with logo, stubby sparker knob, and the fuel tube attaches to the burner through the large opening – but near the right lower edge of the opening instead of near the center.. Here are links to the pictures: 1973 MSR Model 9 first half Model (left) Late model (right) picture 1 1973 MSR MODEL 9 picture 2 1973 MSR MODEL 9 picture 3 To see an English translation of the complete blog post: Do a Google search for trail1.naturum.ne.jp On the first found item, click Translate this page Scroll down until you see Category in the first column Click on Camp stove(16) Scroll down to the last blog entry dated July 13, 2009 New MSR Stove – MSR Newsletter #7 April 1973 MSR Newsletter #6 May 1972 did not contain any mention of stoves. The Model 9 first appeared in Newsletter #7 April 1973, posted here MSR 1973 by @Giri. This newsletter has several pages on stoves in general and introduces the New MSR Stove and related items. The newsletter contained pictures of the New MSR Stove with an MSR pan (page 7-8); the Heat Reflector on the burner, and the Wind Screen around the burner (page 7-9). These pictures were used for the Model 9 instructions and continued to be used for some following models 9A and MF that came afterward. Here is my recreation of the iconic stove picture using my stove and MSR pan: The stove and pan picture, at higher resolution, was also used in several MSR web articles. Here is one that was included in a post by @OMC: If you click on the picture to zoom in, you can see the sparker has a slender knob and the sparker is longer. There are also what appears to be two small holes in the housing (body) to the right of the air hole which has the flint holder. This is the only Model 9 picture I have seen that has two small holes in that position. The logo sticker on the pan (in black and white) looks like the one I have wrapped around the fuel tube. There is a logo sticker in color in this post by @oddball. (The orange helmet shows through the transparent part of the sticker.) MSR Cooking Utensils I was also interested in some of other MSR items I have. On page 7-9, Newsletter #7 describes 2- and 3- Quart Pans with lid – no handle, metal thickness .023”, chemically grayed outside for better heat adsorption Lids – D-ring handles taped for insulation Pot lifter, aluminum Fry Pan or Plate – Teflon II coated, not blackened on outside, medium weight aluminum Aluminum cup (like the burner cover) Heat Reflector & Wind Screen – flat ring and collar, 9”diam x 6.5” high, .006” thick Bottles, PVC Aluminum Fuel or Water Bottles – 1 and .6 quart, with or without rough identification band for fuel use, and individual self-adhesive bands. There is a picture on page 7-9 of newsletter #7 of various cooking utensils. Here is my recreation of that picture, except there are three lids and no fry pan. I had one of the fry pans, but having been scratched beyond cooking duties, in was in the garage holding “junk” and was thrown out during hurricane Harvey cleanup. Full disclosure: I’m not sure if the pot lifter and lids came from MSR. I have a vague memory of going through a stove/cooking display (including MSR stoves) in an outdoor store and may have gotten them there. The pot lifter is stamped CANADA on the top handle and does look like the one in the newsletter. The lids do not have taped D-ring handles. In any event, the pot lifter and lids are from this time period. End disclosure. There is a black and white picture on page 7-2 of newsletter #7 of a fuel bottle with a rough identification band. The pictures above of my quart bottle have two red bands with raised white dots. I have no idea why there are two. And, I believe, here is a bottle with one such red band in this post by @kjhriverrat: I found another example on the internet - a picture showing a fuel bottle with a red band-white dots, a model 9 stove (with slender sparker knob, what I believe to be remnants of a logo sticker on the fuel line, a white pump with square knob), a tin can lid simmer plate and a pot lifter all arranged on top of model 9 instructions. Here is a Link to the picture on a BMW Motorcycle Owners of America forum. 1973 Advertisements in Off Belay and Backpacker In late 1973 these magazine advertisements posted by @oddball show a Model 9 with slender sparker knob, a longer sparker and an MSR pan with shading about 2/3 the way up from the bottom (i.e. darkening for heat adsorption): December 1973 article in Off Belay One of the items published in the booklet Stoves for Mountaineering (Off Belay – 1975) was a section reprinted from the December 1973 issue titled Lightweight Stoves for Mountaineering. The MSR Model 9 is discussed on page 20 of the booklet. Click image to view large size. The stove in the pictures has a slender sparker knob, a longer sparker, a band on the fuel bottle, and what, I think, is an MSR logo sticker on the fuel tube. I believe this shows that some early Model 9s had a logo sticker on the fuel tube and a longer sparker with slender knob. Burner Details Next I will show some of the details of my burner. Here is a picture of the catch end of my fuel tube. Note the taper at the very end of the fuel tube. The fuel tube diameter of 0.250” reduces to 0.213” over about 0.2”. This is about a 5 degrees taper, if my trig is correct. Other fuel tubes I have seen pictured are slightly rounded at the end but not tapered. Also note the parallel ridges at the edge of the block, and presumably extending inside the block. The near side of the block has three indentations. There are 2 O-rings on the catch wire behind a metal retainer. You can see a part of the MSR logo sticker on the tube. In thread MSR No. 9 – Up Close and Personal, @idahostoveguy posted a similar picture of a stove that I noted in my first post also appeared to have a logo sticker. I am now convinced it is the remnants of a logo sticker. The end of this fuel tube is not tapered. @idahostoveguy commented about the O-rings: The reason for O-rings on the catch is explained in the Instructions: The O-rings should be the size needed for the pump that came with the burner. I took some measurement that will be reported below. The sentence in 1973: Remove by stretching over the retainer. is not in the 1975 instructions: I believe this is because the use of a metal retainer was changed to use of a short piece of fuel line tubing, making it much easier to remove an O-ring with less risk of damage. Here is a view of the fuel tube passing through the housing. The tube connects to a larger round section with concentric ridges around the circumference. That section then connects to a rectangular block. Also, if you zoom in, note the scratchiness of the two pimples and the two small sections holding the pan wires at the top of the housing. @idahostoveguy commented about pimples on the housing: I think the scratchy-shininess is caused by rubbing as the aluminum cup cover is put on and taken off. I suspect the pimples are to help hold the cup more securely during transport. Here is a closeup of the fuel tube passing through the housing where you can again see the parallel ridges of the fuel tube. Then the ridges stop for a section of what appears to be the original diameter. Then there is a shorter section of smaller diameter. Then another section of what appears to be the original diameter. This section may be a different material since it appears to be a different color. There may be a joint in the fuel tubing in this area. Going outward from the housing, the fuel tube slants downward a little. Here is the next air opening going clockwise. You can see the fuel tube connects to the larger round section with concentric ridges around the circumference and then to a rectangular block. The block has a few vertical lines on this face. The block sits on top of a dome nut, below which is the asbestos priming pad. The cotter key is visible in the shadows on the left. Here is the next air opening going clockwise. You can see three interesting indentations in this face of the block (the lighting has to be just right), a clear view of the cotter key, and the jet just visible inside the burner cap. Cotter Key or Split Pin or Cotter Pin The reason for the cotter key was posted by @hikerduane:i The official explanation is in the instructions: Later “wires” was changed to “cotter key” (also known as split pin or cotter pin): Flint Here is the air opening with the flint holder. You can see the knurled finger cap on the flint holder, the sparker internals (very dirty), and the bottom of the bell, block, and fuel tube. Here is a closeup of the flint holder. I include this so you can see the scratch (just past the cap) that I made removing the stuck cap to check the flint. I don’t remember ever changing the flint before, but I read a warning in a post by @Doc Mark about ruining the sparking wheel: My old piece of flint was only about .080” long which is less than the diameter .0935”. (I saved the removed flint piece in a baggie.) I installed a “new” flint using a 1980s vintage Ronson flint I had from car camping. The new flint is .243” long, so the old flint was well past the recommendation to change when “half used”: Second Asbestos Pad Tilting the stove up a bit, the next picture focuses on the pad between the fiber base and bottom of the housing. A picture like this was posted here before by @Pinky: And commented on before by @taku: I suspect the asbestos pad is there to insulate the fiber base. Pump Issues and Testing White Pump – Initial Failure, Leak at Control Valve The white pump pressurized an empty fuel bottle ok, but when I tested it with a little fuel, I found a leak at the control valve. I set the white pump aside and turned to the yellow pump. Yellow Pump – Never Used Pump Cup Needed Lots of Oil I tried pumping the yellow pump, not attached to anything, and found the plunger did not have any resistance most of the time, even after oiling. So I removed the plunger, oiled the pump cup, and massaged the leather. After a few cycles of this I finally got some resistance. However, no air was coming out of the end with the missing air hose. Yellow Pump – Check Valve Issues So, after reading several sets of instructions here on replacing the air tubes, I decided to take the check valve apart to try to diagnose the problem. Pulling the pins was easy because I have a musical instrument fret puller (basically a flush ground end nipper) designed for removing frets from fingerboards. When the pins were removed, the rest of the broken air tube crumbled into tiny pieces. The brass ferrule and spring were easy to remove. But the Teflon disk was still inside. I think it was stuck to the O-ring, which preventing the pump from pushing air through. I managed to get it out by blowing down the pump body. I didn’t lose the Teflon disk, but for a moment it was hiding under my knee as I was sitting on the floor at the time. I decided that if the Teflon disc was really sticking to the O-ring then I needed to replace the O-ring so I removed it with a safety pin. I tried and failed to find some fuel line and Viton O-rings locally. I did get a correct size O-ring from my local lawnmower repair place but he didn’t know the material. I decided to test fixing the check valve with the new O-ring before ordering fuel line and O-rings online. I inserted the new O-ring with the blunt end of a wood skewer. Then the Teflon disc, spring and brass ferrule, again using the wood skewer to push and hold it while I inserted a section of 2” paperclip through the pin holes and bent the paperclip piece to hold it all in. At this point, the pump pushed air out the end! Time to Test – But – Safety First I read multiple warnings here about using old pumps. I wanted to make sure my stove still worked. I thought about getting a new pump, and I would do that if I were going to use the stove in the field. But, I thought I would see how far I could go safely. At this point, let me say that I worked two summers as a lab technician at a chemical plant, was a chemistry lab assistant in graduate school, have two degrees in chemistry, and worked 35 years for a company (non chemistry job) that stressed safety. First I made sure the yellow pump could pressurize an empty fuel bottle. Then I put a small amount of fuel into the fuel bottle – not enough to reach the check valve or pump bottle gasket with the bottle on its side. I added some pressure with the pump, tilted the fuel bottle down and, after tightening the bottle gasket a little more, found no leaks at the bottle gasket, control valve, or fuel socket. I then attached the burner. I decided to test the stove on top of my gas grill outside, with the burner on the grill and the pump hanging over the edge so any leaks would drip away from the burner. If needed, I could close the grill top over the burner. I also had a hose ready on a table near the grill. Here is the stove pre-heating. And here is the first blue flame and roaring in almost 40 years! White Pump – Control Valve O-rings At this point, I removed the white pump control valve. It has two O-rings, one around the stem of the control valve and one at the bottom of the control valve socket. They are the same size as the O-ring in the yellow pump check valve. Online, I ordered Viton O-rings OD 1/4”, ID 1/8”, CS 1/16” (AS568-006) for white pump control valve and yellow pump check valve OD 3/8”, ID 1/4”, CS 1/16” (AS568-010) for white pump fuel socket (More on this size later.) OD 1 5/16”, ID 1 1/16”, CS 1/8” (AS568-215) for pumps and fuel bottle caps and a short piece of 1/4” OD, 1/8” ID Tygon Fuel & Lubricant Tubing F-4040-A (equivalent to Excelon Fuel & Lubricant Tubing according to USPlastics.com). Yellow Pump – New Air Tube and O-ring I redid the yellow pump check valve with a new O-ring and fuel tubing. I don’t have a punch to make holes in the tubing, but I have a set of 15 drill bits from 1.05 mm to 2 mm. I used a size large enough that the pins would push into the drilled opening. I am not entirely happy with this repair because a plunger push sounds more like a “splat” rather then a normal “whoosh”. I have not tested this pump after adding the air tube. Gap Between Catch and Yellow Pump Earlier, when attaching the fuel tube to the yellow pump, I noticed that the catch did not latch solidly. Here you can see there is a gap between the catch and the pump housing. I calculated the gap to be about 0.060” by taking the distance from the fuel tube block to the inside edge of the catch wire, 1.180”, and subtracting the distance from the fuel socket to the inside of the catch indentation on the pump, 1.120”. Eventually I realized the catch could be secured tightly by putting a small piece of fuel line tubing (1/16” wall thickness) onto the catch wire. Here is the burner attached to the yellow pump the new air hose and a short piece of tubing on the catch wire. White Pump – Revisited After getting the new O-rings, I replaced all the O-rings in the white pump, lubricating them with silicone grease. I tested the stove again and did not see a leak at the control valve. I carefully fired up the stove and did not see a leak at the fuel socket. I took a few pictures and turned the stove off. Later at night, I fired up the stove to take some flame shots. (Pictures later!) When I turned the stove off and moved it under the back porch, I realized that there had been a small leak, probably at the fuel socket. Later, in daylight, I looked for the leak. I fired up the stove. Every minute or so, I checked for a leak by touching the underside of the fuel socket entrance with a small piece of brown paper bag. After a few minutes, I saw a small amount of darkening of the paper from fuel at the fuel socket. No drips, just a small amount of darkening. White Pump – Revisited, Again After several days of thought and looking again at measurements of the fuel socket and O-rings, I realized a few things (new to me). The O-ring ends up on the fuel tube about half way from the block to the end. Even screwed in all the way, the brass bushing does not compress the O-ring. There is a gap behind the bushing of about .119” which is well over the O-ring thickness. The brass bushing also does not fit tightly around the fuel tube. These two things explain how one poster was able to fire up his stove without a bushing: The bushing keeps the O-ring from falling out, provides a solid landing place for attaching the fuel tube block, and provides support when tightening the pump onto the fuel bottle and moving the stove around. I decided to take a closer look at the O-rings on the catch. I removed the first one; it was noticeably larger in diameter and had a fatter cross section than the original O-ring. It also had a smaller ID than both the original and new O-rings. I lubricated the O-ring with silicone grease and installed it in the fuel socket. I gently screwed in the brass bushing in all the way. When I connected the fuel tube to the pump, I saw that, like the yellow pump, there was a gap between the catch and the pump housing. Again like the yellow pump, the catch is secured tightly with a small piece of fuel line tubing on the catch wire. I tested the stove again and this time I didn’t find any leak. Here are pictures of the stove with non-leaking white pump and a closeup of the burner. Now there is only one o-ring on the catch wire. What fixed the leak? I don't know. Maybe the O-ring was a better fit. Maybe the lubrication was better. Maybe the tighter catch minimized fuel tube to fuel socket play. To investigate O-ring size I measured the original fuel socket O-ring, the O-rings from the catch and the new O-ring I had tried before using a digital caliper. I found that with each O-ring there was a small variation in outside diameter, inside diameter, and cross section depending on where I measured it. I tried my best to average out the differences. Here are the measurements and the factory specs for the new O-ring. O-ring - - OD - - CS - - ID Original - .3605 .0660 .2275 Catch 1 - .3750 .0745 .2260 Note 1 Catch 2 - .3770 .0725 .2315 New - - - .3745 .0690 .2335 Spec - - -.3790 .0700 .2390 Note 2 Note 1: ID for Catch 1 was calculated from OD and CS; I did not measure it directly before putting into the pump. Note 2: Factory tolerances are +- .003 for CS and +- .005 for ID. Therefore the spec ranges for the new O-ring are CS = .067 - .073 ID = .234 - .244 OD = .368 - .390 Compared to the New O-ring that leaked, the Catch 1 O-ring (that does not leak) has a slightly larger OD, a significantly larger CS and a significantly smaller ID. In retrospect, I wish I had tested the white pump with the Original fuel socket O-ring after the control valve O-rings were replaced. That would have been another data point and might have helped figure out the proper O-ring size. Flame Shots!!! To get some flame shots with the fixed white pump, I set up outside on a metal table just before dark. I took these pictures with my phone set up on a small iPad stand. I tried to angle everything so the jet would be visible inside the burner bell. Preheating. Pretty blue flame just after preheating. Right side of case lit by a small flashlight on the table that I forgot was still on. Glowing bell. Glowing bell, blue flame. Lit with small flashlight from front, this time on purpose. Fuel turned down, glowing bell, yellow rimmed flame spreader. Here is one final shot from above with full flame. You can clearly see the impacts of the bell scallops and flame spreader arms on the flame.