Hello all! Just stumbled on the forum as I was trying to locate some troubleshooting info on a stove I picked up recently. I bought a Coleman 425B at a garage sale recently and decided to try and fire it up. Let me preface by saying I haven't used a stove since my scouting days 20 years ago. Filled up the tank, pumped it like 50 times but never really felt resistance at the pump. It lit, but was a weak flame that never turned blue. So I thought it was a pump issue and bought a replacement pump. Well, that doesn't seem to have worked. The only thing I really notice is that when I open the knob to pump some more while it is lit, if I'm not careful and quick about it, the burner will go out. I am wondering if there is some kind of check valve or something. I also noticed the cap to the tank has a screw, unlike my lanterns which don't. Does that screw need to be adjusted? And there doesn't appear to be any kind of gasket or o-ring to seal the cap. Any help anyone can give me would be greatly appreciated!
Hello there and welcome. You're right about there being a check valve in the pump. It's at the far end of the pump tube and is of metal (brass) with a steel ball as the moveable element, which allows air to pass one way on pumping but doesn't allow the compressed air in the tank out (if it's working). It can be removed with a tight-fitting screwdriver, but it's screwed home really tight at the factory and it's easy to burr over the screw slots in the brass body of the valve. Best bet is to free it off if it's sticky and I've found this topic summarises the process really well. There's some expert advice in there from the likes of 'flivver' and 'lance'. Highly recommended! https://classiccampstoves.com/posts/116792 Now, how about that tank filler cap? The screw isn't an adjusting screw, but holds the inner seal disk in place. If you screw the cap down on the tank filler neck, it should be possible to loosen the screw then, with the cap removed, undo the screw and release the disk to replace the seal. That said, it's perfectly possible to replace the seal without undoing the screw at all. A working seal is essential to enable the tank to be pressurised and restore the inherent safety of the design. Sometimes, I've used an 'O' ring of a petrol-resistant nitrile as the seal, but a Coleman spare should be obtainable. Alternatively, we'll often make our own seals out of nitrile sheet here at CCS, but a set of leather punches is needed for that. Good luck! All the best, John
From your description it sounds like you should try the o-ring first. I bought mine from oldcoleman parts.com but there are other alternative sources. Smarter gents than myself on here can steer you in that direction if you so choose. They should be along shortly.
Hello, and Welcome! I'm echoing John and guessing you have a air leak. You can get a replacement cap at Wally world for a few bucks, or you can fix the old. One trick, after dissembling the cap, is to heat the inner disk up, and the old seal will pop right out. The NRV (non return valve) removal requires a very wide blade screwdriver, and parts are available at Coleman.com. The 425 is a good-un, I've had mine for ~ 35 years!
Hello PSI, I've got several old Coleman suitcases and the problem is a common one. Try a tank cap from another Coleman product which you know works well. They are all virtually the same and almost all of them will work. I'm betting that the tank cap you've got won't hold pressure due to it's age and the seal has hardened. I've yet to ever experience trouble with a Coleman NRV. If there's ever a pump problem, it's always been the leather cup. As long as you feel good resistence when pumping and it "feels" like it works, it's probably fine. If it is the tank cap, the problem is an easy fix. Baja is right, I've got a 425, 4M, 417B, etc...all basically the same with minor differences...they are fantasic stoves and will last a lifetime!
From your decription, it does sound like the check valve is not sealing properly. But the gas cap is also likely to be in need of replacement and that is the easiest fix. You can work around the check valve just the way you are doing it, pump and close the manual valve with your thumb in place. A little liquid wrench in the pump tube and the check valve may start working again with a little use.
