Hello I just aquired my first Coleman stove. It's marked US-1944-Coleman, so I guess it's a 520 or M1941. However it will not build pressure and on the two last pictures you could see there is like a little crack or seam in the pump tube. Should it be like that or is it the reason why pressure are not build up?. If it's a crack, is it possible to change tube, or is it just to put the stove in sparepart bin for eventual future use? By the way, I was not able to find instructions or any explosion drawing on this stove here to my surprise (I don't think they are very uncommon in US), is it because it's a military one, or does it just not exist? Best Regards Joakim
Hello Joakim. here are the instructions for a Coleman 520, Just page down to stoves. http://pages.suddenlink.net/abosch1/ColemanPaper.htm Hope this helps.
I've got 1-2 of these stoves though I'm miles from being anywhere near an expert, but I think that crack looks pretty terminal... Now that I've said that, I bet one of our ace fettlers will tell us it's an easy fix!
Its hard to tell from the picture (with my poor eyesite) however,if there is a crack I'm not sure either if it can be repaired. If it is not a crack and just a seam, then it might be the fuel cap gasket is brittle and will not seal correctly.
Can't tell from the pictures, but 1) Is there a good leather on the piston for the pump? Looks like maybe missing? 2) Check the rubber gasket of the fuel cap. These 2 things account for probably 80% of Coleman "failures" Both easy to fix. If there is a crack in the tube inside the tank then I think you have a table piece. Good Luck, Jim Henderson
Thanks everyone I will try to blow little compressed air into the vapouriser hole and see if it leeks from inside out. Best would have been if it just was to get a new tube and solder on as with primus stoves etc. Henrik, I will get another one of these and will keep thisone as spare until then at least. Othervise I know some part will fail which I could have had use for. But I'll let you know. Best Regards Joakim
Are the pumps not just soldered into the tank in Coleman stoves as in most others? I guess they could be welded if the tank is made out of steel... Someone has to fill me in here since I'm not very familiar with them, but most other stoves admit their pump barrels to be desoldered out from the tank quite easily. If this is doable, you might be able to fix the crack even if it's a bit tricky. I have done this with a couple of Primus lamps with success. But they are paraffin fueled. Not absolutely sure I would rely on a tin soldered crack in a petrol stove...
I do not see a fracture in this pump tube perhaps if i were to have the stove in my hand i might see such. Is it repairable? Yes. If you don't feel you have the qualifications to repair it by al means send it to one of our great fettlers for a fix. From what i see you have other issues than a possible a fractured pump tube. lance
Hi all: Interesting post. Out of hundreds I have never seen a cracked (Coleman) pump tube. My guess is problem is as previously stated ,either pump leather, cap seal or stuck check valve. All easy fixes. If It indeed has a cracked pump tube please post close up picture of the crack. The blemish in the photo looks like the normal seam to me. Mike...
Thank you Flivver I just removed the checkvalve and there seems to be no spring at all holding the ball into place. Probably (if it works as primus checkvalves) the rubber/leather will be stiff as well. Anyone who could tip on a seller on ebay (or anywhere) who got this kind of Checkvalves for sale? Best Regards Joakim
Hi: There should be nothing holding the check ball no spring ,rubber, leather etc. It should be loose, free to rattle. If so blow through it from the back side, if flow is restricted it is working fine. The only thing that causes these valves not to function is dried incorrect fuel type that intraps or inhibits ball movement. In that case soak with "lacquer" thinner. Do not under "any" circumstance try to open valve to remove ball. In repairing hundreds of Coleman stoves I have "never" had to remove or replace the NRV (they are indestructible) unless it was destroyed by someone trying to remove it. Coleman stoves almost "never" need any but the most basic disassembly to return them to perfect operating order. Such as removing fuel cap to replace gasket or oiling pump leather. NRV/ check valves do not have to be removed, just fill with "lacquer" thinner and let soak. I am continuously "horrified" when I read about someone doing major surgery on a Coleman for a 30 second fix. Coleman's that have been used with "proper" fuel just don't need maintenance excepting maybe a yearly drop of oil on the pump leather of older models that use leather. I once dug up a battered/rusted Coleman stove out of the mud in a western Oregon junkyard, washed the mud off, filled the tank and cooked hotdogs after the yard owner bet me it would never run again. I got the parts I had picked out for free! Mike...
Mike - can you have a look on your tin of lacquer thinner and tell us what its constituents are? In my search for 'lacquer thinner' in the UK I found all sorts of different concoctions under that name so I was never certain I would be spending my hard-earned on the right stuff.
Hi I took some thinner (don't know the exact ingredients) and let the NRV swim there overnight, it worked perfectly. But now when I'm able to have some pressure I noticed there ain't no real flow through the vapouriser/generator (is it exactly same thing in english?). So I mounted it down and the fuel pickup tube looked to be quite dry and corrosive. At the bottom tube there is a little spring which function is unknown to me. I don't really know how to disamble that lower tube completely either, but perhaps it will show when it's cleaner. So I will clean the parts up as best I can and see if it will make a better flow. They are complicated those little Coleman stoves I must say, or could it just be a my total lack of knowledge about them? I'm a'fraid I will keep this thread open until I could show some nice flames. Thanks for all answers so far and your patience. Joakim
Inside the fuel/air pickup tube (its actually a tube-within-a-tube) there is also a long rod that reaches to the fuel entry hole and acts as a restrictor. When the valve is only 1/4 turn open, the valve shaft pushes this rod down and the entry of fuel into the pickup tube is restricted, but not blocked. The inner tube 'slurps' up this fuel but also sucks up air as well, which enters the outer tube through the hole at the top. A mix of liquid fuel and air bubbles is sent to the generator, this mixture is much easier to vaporize than liquid fuel alone so the stove preheats quickly. When the generator is hot and vaporizing, the valve is opened the rest of the way. The conical tip of the valve shaft comes back over the top of the restrictor rod. The spring pushes the rod upwards and the fuel flow is no longer restricted, the slurping of air stops and only liquid fuel is delivered to the hot generator. Closing the valve pushes the restrictor rod back down again. So to start, open the valve 1/4 turn and look for a spluttering fuel delivery through the jet. Light this carefully, you will have a big yellow flame spitting and roaring at you. Once it settles down to blue, give it another ten seconds then open the valve the rest of the way.
Joakim the fuel-air tube in the fount or tank unscrews from the valve assembly. This will allow you to clean the tube and the restrictor rod. It will also allow you to streach the spring a wee bit. When reassembling the spring goes atop the rod and then the fuel-air tube is screwed back in place Do not over tighten this tube. Make it snug then a quarter (1/4) turn is all that is necessary. lance
Hi all/David: I am sorry about "thinner" maybe Lacquer thinner is not available in Europe. In the U.S. older style automotive paints were lacquer based and required a stronger thinner to cut them. Most modern thinners will not soften dried fuel. Lacquer thinner will soften and dissolve it. Lacquer based paint s still used here to restore antique cars so the "lacquer" thinner is readily available at any hardware store. Also this type thinner is a popular cleaner and solvent. I use it to remove oil and grease from my concrete driveway. The can states "Lacquer Thinner is a high-solvency, medium-drying thinner for lacquer. Designated for the thinning of industrial maintenance coatings." It lists partial ingredients as follows: Acetone,Methanol,Petroleum distillates and Toluene. I hope this helps. Mike... P.S. AS IT IS POISONOUS USE GLOVES.
Nail Varnish remover is largely acetone - might be worthwhile having a rummage in your wife's drawers as it might do the same job? Cheers, Graham.
