French military stove 7052 repair (burning yellow)

Well I am going to finally have a crack at this thing as I've had it for a few years now and thought to put this to the forum before I start silvbrazing all over it.

Since no one in the forum has broken one down...I did it. And this thing is a beautiful pain in the ass (like my wife) haha.

So...the problem is that it basically works like a Coleman 425. Other than the burner is above the generator so under the burner there are little holes to let little flames out to keep the generator hot... But more on that in a second

Disassembled and cleaned. The three screws that hold this in place have nuts in the hardest places to hold.



So again... Without the shroud... It's like a Coleman.. except it needs a preheat cup and the generator is under the burner



To get air (I guess) there is a gap between the generator tip and the pickup tube



The pump is very short... But luckily this stove takes any NRV (I tested a NRV from a Primus 210) it just likes the one it comes with as the spring is a lot more relaxed



This thing has asbestos for a valve seal and it was quite dry... Very dangerous as air leaked out. I planned on changing it anyways so this is what the generator looks like out. It "had" a cleaning needle at the tip... But it was long gone.



More later....

 

So assembled...

 

Problem...
So the holes the generator go through... One is right 8mm... the other is really a lot bigger...and flames come out of it. I'm going to assume this is why it burns yellow.

Whatcha think?


BTW this thing also reminds me of a blowtorch in the tank set up....

 

My thoughts are to get a brass tube with 8mm ID (like the generator) and something like 9-10mm OD. Expand the holes, silver solder it place, trim it off so to seal off the leaks.

 

Wow, yours is in a lot better shape than mine, haha. I wiped mine down, replaced the NRV pip, and fuel cap seal. Need a leather pump cup, but may be able to use the one I have.The extra in the spare parts container has a hole too small for the brass gallery to fit through. Guess I could drill it out. Also, I saw a video on youtube, for one of these stoves, and it showed that the gap for the air mixture should be 4-6mm.

 

So, a tube span the two holes, entry and exit. It would ensure alignment for the generator to be inserted and there’d be absolutely no escape of the combustible fuel/air mixture to ignite.

 

@presscall Yeah. Silverbrazed at both ends, then trimmed off. Looking at 9mm OD with .5mm thickness, so inside will be 8mm. Can fit it from there. I think once I clear out the flames I can further diagnose.
Does it make sense to you?

 

@The Warrior can you put the video link up? I'll give it a watch... never know if I missed something

 

Sure do. It's in Japanese. Doesn't seem to have a yellow flame problem, but at the end of the video it shows the gap size.



I took the liberty of downloading the video to my desktop, took a few snapshots of the video, and translated them:

 

Yes, perfect sense.

Just a couple of points though:-

1. Would the tube interfere with mounting the burner?
2. Would the tube hinder heat transfer from the flames emerging below the burner intended to maintain vapourisation of the fuel vapour in the generator?

 

Thanks @The Warrior I'll have a look

 

@presscall thanks... sometimes it does good to think out loud so others can either agree or give input... I'm not one to shy away from asking questions

So to answer
1) no it would not interfere as I'll trim the tube down to almost flush, but in the assembly and disassembly of the burner from the pot stand the only issues would be if the preheat cup would somehow be blocked (absolutely not near it). The distance from the burner bell edge and the pickup tube area are the only problem that installation would be an issue. I have not made the repairs yet as I'm waiting on parts, but im confident I'm correct in this based on my measurements and having the item in hand

2) the burner as far as I can tell is like a Coleman but that the generator goes through the burner underneath. To keep the generator hot these 7 holes plus the 2 others somewhat surround the generator tube with blue flames. That ragged hole is also leaking gas and has a big blue flame there as well... Way too much. I'm guessing the way it's supposed to work it's not supposed to have all these flames under the bell. I'll try to get a photo of it burning later for you.. You'll see what I mean but here is a closeup of the small holes the manufacturer made to keep the generator hot

 

@Remus1956

My 7052 also has a hole in it, which helps keep the vaporizer hotter during combustion.

 

@Camp numao mine has flames coming out of the big hole on both sides and the little holes...I think it's bad haha

 

@Remus1956 "Almost" safe but the fuel tank is still too close to the flame(if you ask me...).
As for asbestos, europeans spend billions euros to get rid of it. while the rest of the world doesn't really gets scared of it or the lung cancer "option"/possibility...
Truth is, there almost isn't any other material to protect you from about 7-8 tons of steel alloy heated to 850-900 degrees Celcius freshly pulled out of a huge furnace and moved around to the polymer heat treating pool. Was 3 meters from it and almost burned me/my skin. Guy doing the work had one of these old asbestos clothing and didn't even sweat. No pictures,because its private company ,"secrets" of heat treatment ,etc...
But without asbestos things are hard...
I am curios about that generator. Is it "cleanable"? Or like many sugest in Coleman ,"just replace it"?
And as a personal curiosity: how many stoves you own now?
I gave up using Shmel-2 gasoline stove. too scared of burns and the fuel tanks got too hot while in use for my "nerves"...
Back to Lpg burner... For now :-)

 

Yellow flame is surely too much fuel and too little air for combustion! I would wear thick leather gloves while testing. and clothes to cover any skin left exposed. As for face protection... it's up to you. :-)
I would only use a diesel burning stove in future. Had enough of "surprises" with gasoline or denaturated alcoohol.

 

@The Warrior that japanese guy is shocking... testing for leaks with a lighter/flame is insane...

 

Hello @Gabriel Lorin that was quite the lengthy post! I will try to answer your questions.
So in regards to the flame being too close to the tank for me in my opinion its a little farther from the tank than say the optimus 8r or 111. The valve does work really well but I will get back to that in a sec.
I totally understand what you mean about the asbestos. I have a couple of stoves that still have it in there, but this stove didnt pass my personal "testing" haha. One of my tests before firing up a stove it to put 50ml of fuel in it and just pressurize it and wait. I give them about 10-15 minutes and check for any leaks. If no leaks it goes to stage 2 where I turn the fuel on and off. This particular stove did not pass as the minute I pumped it up it leaked fuel directly out of the knob valve regular. When I pulled the valve apart it looks like it was graphite impregnated string (seen this in lots of euro stoves to include meva and soviet stoves) It was so dry and the knob spun so freely I knew this would have been an issue and planned to replace it anyway but I do follow a process.
The generator is absolutely cleanable! It comes apart and I cleaned it with steel wool around the rod and boiled the coil around it thats used to wick fuel to get any carbon off. Once cleaned it had a steady stream and turned on and off really cleanly (no candle flame)

Uh haha...I never really counted them but I do have a lot of stoves and lanterns. Just not a lot of duplicate ones.
In my office I have more than 40 of them near me as I type this. And for me I am trying to not own duplicates (somehow I come into Optimus 8r's all the time though...I think I have 5 of those)
8 or so enders (9063, 263, 9060's 9061 and one of those Desca looking enders alcohol stoves)
A bunch of primus stoves (96, 97, 210, no1 SOR, 8rs, 71 in late optimus 80 tin)
Optimus 111, 111T, 111b, 96's, 00's, 8r's and a rarer Optimus made in Vienna
British monitor 17, veritas duo burn (like 96), burmos 21, and one of those big green cased military ones (not sure but its a roarer)
German Bats (45/2, east german bat like no1 primus size but with a silent burner)
Aida 100
Petromax 100
Juwel 33, 34
Polish Deba (favorite)
SVEA 123, 123R, 106
Radius 42, 43, 17, 20, 21
Coleman military medical stoves (never posted those), 500's (canadian) 508's, 400's, 1950's and pocket stoves
Soviet Shmel 1 (not the phoebus clone) shmel 4, PT-1, and PT-2
French Vesta's and now this 7052 military stove
Austrian Phoebus 525, 625, and 725
Czech Beverex 1 and Beverex 2

I got a lot of lanterns, but mainly just stick with Coleman Quicklites with the mica globes (my wife can rebuild them) and those kerosene gas lamps made by Coleman.

I make coffee on a different stove every day unless its raining and keep an eye out for stoves I dont have.
If you have a shmel 2 you dont like, I can trade you something for it! Thats one I dont have on my list.

 

@The Warrior I wave a flame near the knobs but only with a spritze of carb cleaner in the tank when testing...