Coleman 425E stove pump cup and FA tube. 

I've had to replace quite a small number of leather pump cups, maybe 3 or 4 out of more than 50 lanterns and stoves. I've gotten a couple lanterns and stoves that just didn't have a pump cup at all but usually if a leather pump cup is present it'll revive. The neoprene ones, not so much...

Leather pump cups last practically forever when kept oiled, or I guess, greased.

I've had the best luck with nests foot oil. I started out using ATF but found i had to reoil often. With nests good oil I can go a couple years between oiling.

You can order a set of 5 at Amazon, new ones. Great if you have a few old Coleman's to rehab.

The lab labors in lantern love

LOL Talk about exacerbating a bad situation!

You can get the leather pump cups from Old Coleman Parts. Tell Mike I sent you. A 425 like this is the perfect size for most griddles and its easy to take the lid off. For a dutch oven I prefer a 413, the extra size means I can fit two medium size dutch ovens at the same time. The tank is much larger on a 413 and lasts a lot longer.

Thats actually a MAPP gas torch although I mostly use it with propane. You'll have to pull the valve out of the tank and ensure that the rod goes down into the FA tube and that the tube is open at the top. Pull the tube off and blow some air in through either end while plugging the other. The air should come out sideways near the top. Often just blowing some pressure through will dislodge whatever crud is there, if not soak it for an hour or so in some vinegar or citric acid, or CLR or whatever other mild acid you've got handy. Rinse good and try the air again. Repeat until the FA tube is clear. When pulling the valve DO NOT put pressure on the generator, you'll break it, ask me how I know. An adjustable wrench on the square block on the valve assembly will be your friend.

Sometimes the old fuel isn't a huge problem, I have a military stove that lit with the 30+ year old fuel that was in it...

Time for the dunk test, I've got a video on it. Pressurize the tank, dunk it in a pail of water and look for bubbles. Might want to pull the pump and see if the check valve is leaking too. If there are no leaks then it's that the FA rod isn't lifting. They lift on spring pressure so its easy for them to get glued into the tube.

Old Coleman Parts should have the check valve. There isn't that much heat at the valve, the tank has fuel in it which keeps things relatively cool, its also pretty big and thus can shed heat well. I've been using locktite for valve to fount connections on lanterns for years.

Wanting a new check valve for a very old stove . Thanks for your reply .

Not unless you get a bunch of food in them. My 413E has a lot of hours on it and hasn't needed cleaning.

Thank you!

Hey, I'm originally from Maine. We've got land in Caribou.

Lantern Lab that’s great. Someday I’m going to visit Caribou. We are in the lakes region....check out my boring videos to see what I see. 😂

Might have to resort to a little heat. Some of them can be difficult. Don't pull on the generator. I learned that one the hard way.

Most likely from gasoline, Coleman fuel doesn't gum up for a long time, gasoline additives make it gum up pretty quickly.

Any suggestion on how to clean fuel air tube without ultra sonic cleaner? just carb cleaner? My in surging, I suspect the tube is clogged up. I just got the stove from my grandfather and it's been sitting since the 80's with gas in it.

submerge all air/fuel parts in carb cleaner or Seafoam let sit for a few days, rinse and inspect, re assy. clean the stove body with a purplepower /water 50/50 mix.

Whitegas/Coleman Fuel/Crown gas/gasoline/naptha. Theres lots of things you can use. Probably best to start with Coleman or Crown canned gas.

Nope, Mike at Old Coleman parts can hook you right up.

@@LanternLabs thanks. Sadly I wasn't able to find any stove decals there. Mostly lantern decals.

Both of the knobs can be loosened by slightly loosening the metal bit behind them, this will slacken the pressure on the graphite packing that seals the shaft. Don't go crazy, start with an eighth turn and see how it goes. Is the pump working but hard to push or does it just flop down the hole?

Lantern Lab, I’ll try the 1/8 of a turn to see it that works. The pump has pressure as if it fully pumped up. This even happens when the gas cap if off. I did oil the leather plunger. I also removed the check valve stem. Both look great.

Are you opening the valve in the pump enough? You need to unscrew that or you can't pump. If you are then theres probably an obstruction in the check valve.

@@LanternLabs Yes, I have unscrewed the the pump valve too far to the left. I have even tried pumping it with the gas pump off too. In fact just to prove I wasn't losing it I brought it to work and other "Coleman" guys looked at too. We are thinking of spraying some brake cleaner in the pump tube, thinking as you are, something is clogging the check valve. I've heard that removing the check valve is the last thing I even want to think about. I'll keep you updated. Thanks for your help.

I just got home and sprayed some carb cleaner down the tube as well. I let it sit for about 10 minutes. I even removed the square bare that sits in the pump tube. Dumped it out and still not allowing air to pass through. Thanks for any ideas including getting a new fuel pump.

Did you loosen the air stem first? You have to turn the knob a turn or two counter clockwise before you try to pump. Once you're done pumping snug it down again. Otherwise you've got something blocking the check valve.

@@LanternLabs I may have not turned it enough counter clockwise. I tried it again and while it's better, it still doesnt quite feel right. I did use a repair kit. It would be hard for you to diagnose without pumping it yourself I would imagine. I sure do appreciate you commenting back to help.

I am not certain I would post a video of preheating with a torch. Somebody else does it and forgets fuel cap is off and has a problem! Ditto for lighting these stoves/lanterns indoors.

Stoves are a little different than lanterns because there is a needle attached to the valve. As the valve opens the needle retracts so you don't really get as much (sometimes any) gurgle like you get on a lantern.

I use the stuff that came with it, I think its probably a mild acid. Dilute citric acid works pretty well too and is slightly faster than just citric acid alone. Honestly my ultrasonic cleaner isn't great. A friend has one that got surplused out of a lab somewhere, his is fantastic.

@@LanternLabs ok thanks

I had to check what I used in the video ;) Any mild acid will do the job, I like citric acid but vinegar (acetic acid) or CLR (lactic acid) will work equally well. I don't like the strong ones like muriatic acid (hydrochloric acid), its easy to go too far and its hard on any iron in the area. Remember to blow out the passages, thats actually the most important part.

The tank itself isn't really a mechanism. There are 2 potential problems with the pump, one is that the leather is all dried out and won't seal, in which case soak it with something like Neets Foot oil and stretch it a little. You can test the pump by keeping the check valve locked and try to pump with your thumb over the hole, if you can't get the pump to go down much the leather is good. You are holding your thumb over the hole in the pump right? The other potential problem is the check valve might have a massive leak and won't hold pressure. If you pull the pump and put some carb cleaner down on the check valve, let it sit a few minutes and then pump it through that might help. Last though and this is very common, it could be a leaking cap gasket...

I've tried a bunch of things, best seems to be mostly water with a splash of stuff that came with it. Citric acid works good too.

Thank you. What cleaner did it come with. Will water alone do this to aluminum foil? I have a larger cleaner similar to this one. I have not tried it yet. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7SGIcG1QJAA.html

What solutions have you tried that do not work well?