I have a 1980s Coleman 413 that I have been slowly cleaning up - Painting a Coleman suitcase Part of that involved removing the generator from the tank to clean it. I did not remove the valve / fuel pickup. Using the stove I find that after shutdown it weeps fuel from the generator tip over the course of several hours. No other Coleman suitcase stove I have (a modest sample size) does this. I do not know if this was happening prior to working on the stove as I did not use the stove much. I presume this is some form of capillary action but this confuses me. The stove is shut down by turning the fuel pickup level upwards and letting the stove run for a few moments to flush liquid fuel from the generator before closing the valve. There is no path for the liquid fuel to flow along. Could it be condensation of fuel vapour? There seems to me (take that with a pinch of salt) to be too much fuel produced, the tank remains pressurised over a period of a couple of weeks and if left sitting with the generator pointing upwards this does not happen. Is there another potential cause? Has anyone come across this before? -R
If you hadn’t made that distinction I’d have said ‘they all do that’, meaning that it takes what seems like ages for a Coleman flame to die out after closing the fuel valve. It’s the chamfer arrowed on the control spindle mating against a corresponding seat in the valve that shuts the fuel off and it’s possible that a scratch or other imperfection there could result in the ‘weeping’ you speak of. That said, there’s a substantial volume of generator beyond that point to the generator tip and residual fuel in there can take a good while to burn off or ‘weep’ from the gas tip if the generator has cooled sufficiently (air lever up) for the fuel residue to be no longer gaseous.
That seat on the vale that Presscall shows can be less than perfect. And/or If someone previously took the valve out, they could have put it in 180deg off. I would be tempted to remove valve, note when it comes loose from threads, turn 180, and try again. While valve stem is out, inspect for damage. I have opened/closed valves over and over again and improved the situation. Weeping out the end of generator is not gonna be just left over fuel. Good luck!
Thank you all. Plenty of food for thought. I am going to pursue this in a more empirical fashion. Step by step. First step. If this is condensation, then after leaving things to cool overnight and cleaning the liquid fuel from the generator tip no further fuel should be emitted, right? Fuel re-appears within a few hours, ergo it’s not (solely) condensing fuel. #2. Open the fuel cap to release tank pressure. No further fuel is emitted, ergo this relies on a pressurised tank. #3. Re-pressurised the tank, with the fuel lever still upright, open the valve. A jet of fuel is expelled somewhat intermittently… which to me suggests there is something wrong with the fuel pickup mechanism.. or there is a lot of fuel remaining in the generator after I have shut the stove down. I will run the tank dry and take a look at its innards. -R
When you open valve with lever up, it is supposed to mix air and fuel so you don't get massive flames. So intermittently is what it is supposed to do. If you turn lever down and let it squirt a few seconds should turn into a more-or-less steady stream. Your valve is leaking a bit, try taking it out and turning 180 deg (these have two thread start spots) and/or dress that tapered seat a little.
With the start "Up" lever up, you should get a spray, not a solid stream. You need that spray to help avoid flooding the stove. If flooded and you keep at it, the flame will have much yellow in it until that excess fuel is burned off. Duane
I Invite you to go try a couple stove tanks and see. They will spit and sputter until generator gets warm. EDIT just grabbed a tank, it gold round like off a 425nl. Lever up, spit sputter.
I had a little time this weekend to investigate a bit more. I have a newish 424 which emits a ‘wet spray’ when the valve is first opened. In comparison this 413 produces: I noticed that after leaving the fuel pickup in the upright position for ~45 seconds there was no subsequent weeping. A single data point, but something to pay more attention to. In running both stoves side by side I noticed that upon closing the valve to shut each stove down the 413 stops immediately where the 424 lingers for a few moments. This has me wondering if the needle in the generator on the 413 is perhaps sealing the orifice and trapping fuel vapour (which subsequently condenses) where the 424 lets it escape. -R
Needle does not seal generator. "lingers for a few moments" is fine. If stoves don't run for a few minutes, mine at least don't shut off cleanly. Too much fuel from flooding a little, and not yet vaporized. Some of them I originally though something wrong, but if I just run em for a while they shut off cleanly.
