Hi, all. My name is Steve and I've come to a new hobby of collecting (and potentially, restoring) old Coleman camp stoves. I've been an astronomer for years and I'm an avid hiker, who loves to car camp at my hiking spots. Last week, in pursuit of a two-stove setup, I came across a dusty, worn-out Coleman 425F with a build date of 8, and 10, 1993, owing for their stampings on the fuel tank and case, respectively. Upon inspection, it appeared to be intact minus one bailing latch wire on the left-hand wind guard. The tank and case were heavily scratched up, and the burners were quite rusty. Inside the empty fuel tank, everything looked pretty clean for the most part. After a detailed cleaning with a stainless steel scrub pad, and then a drill-powered steel bristle brush for the burner manifold, I filled the tank with a fresh quantity of white camp gas fuel, set pressure per the stove's lid instructions, and set light to the burner as prescribed. Nothing. Not one to give up, it was off to Cabela's for a pair of replacement leather pump cups (one for a spare), to replace the worn-out, shrunken neoprene cup inside the pump assembly. Once the pump cup was replaced, I repeated the process at which point the stove lit, but continued to flood out and produced a yellow flame nearly a foot in height off the burner cup. It did this repeatedly. After that, I decided it was time to rip the stove apart. Over the next few days, I tore the entire stove apart, giving the case, lid, wind guards, and burner plate a new coat of Hunter Green paint (closest match I could find locally in the rattle-can department). I did the same to the tank with fire engine red, after using what seemed like brute force times a million to remove the generator and fuel valve assembly from the tank. (The chosen colors were a near match for the original colors, and I'm quite happy with the result) Once the fuel pump and generator were apart, I used a few bore brushes and carburetor cleaner to remove any and all gunk and deposit build-up. Externally, the drill-operated wire brush was used on the generator tube and fuel valve, followed by progressive sanding, to bring them to a like-new shine. Afterward, I reassembled everything, followed by a test. First test of the stove was very promising, however it still seemed like it wanted to flood out as the flame coming off the main burner was nearly a foot high with definite wisps of soot coming off the flame. It seemed like no matter what, I couldn't get the yellow flame to turn blue, so I tested the notion of preheating the generator tube with a propane torch first. This worked marvelously at preventing the stove from flooding, however only briefly as the flame returned to its prior half-foot to a foot height status within about a minute or so. Then, I paused... Tonight, I decided, after taking a few bore brushes to the hairpin pipe on the manifold and the crossover tube, to test it again. This time, I pumped the tank up, set light to the burner and slowly introduced fuel to the fire. Only this time, I decided to omit the torch in preheating to see how long the generator tube takes to truly heat up. After two minutes, I turned the starter rod down and the flame still seemed way high, so I turned it back up and turned the flame down. After a few more minutes, I turned the lever down and the flame went waaaaayyyy down to almost a wisp of tiny blue dots. After about five full minutes, I had a roaring flame that was mostly blue (solid blue in the auxiliary burner!) but still some yellow remained. The flame looked mostly normal, produced no soot, but I wonder... ...How long does it take for a 425F to reach maximum operating temp? ...Is it normal to have yellow in the flame after the generator is fully heated? If not, what could cause this? I've attached a photo showing the stove after about ten full minutes of operation. Coleman 425F Camp stove restoration project by Steven Rosenow, on Flickr
I have a few Coleman suitcases. They should heat up in around 30 seconds. If you're getting large/yellow flames then 99% of the time it's one of two things: 1) carbon buildup in the generator rod or 2) an insect nest or other debris in the mixing chamber that the generator rod slides into. If you're going to regularly use it for car camping, I suggest getting the Stansport propane converter (it's not really a "conversion", it's just a replacement generator rod that screws onto a propane cylinder) and the Flame King refillable propane bottle/kit. Keep the liquid fuel tank/generator as a backup.
No need to convert to profane. Among other things. Ensure no spider webs in manifold. Ensure the tank is all the way against the case, so the tip is all the way in the manifold. Test the tank by pumping up and opening the valve. Stream shoul come out. Turn lever up, spray should come out. Turn off. When lever is up, air is released. So, you need to replenish pressure during or after priming.
Should only take a minute to get to temp. You should leave the "light" lever up for at least 30 seconds, In your picture, the orange is just crap burning off. Too rich would be yellow. Once flooded (yellow flames) it takes waaay longer to clean up than you would think, and they will burn yellow a loong time, Look in the end of generator, is there a needle sticking thru jet? and does it retract when you open valve?
The generator rod was completely cleaned of all carbon using carburetor cleaner. What else could it be? Yes, that needle is there and does retract. When I disassembled the generator, I insured that all carbon deposits were removed with a wire brush, steel wool (on the needle shaft itself), and carburetor cleaner. The same was done for the fuel pickup tube, which was examined to be slightly clogged but fully operational.
My question(s) were mostly involving warmup times, as mine takes about 3-5 minutes to fully warm up in spite of having fully cleaned all fuel delivery mechanisms. (Also, the burner manifold is not clogged, per a dentist mirror inspection with a high intensity flashlight.)
@Steve Rosenow , I wonder if your meticulous cleaning, possession of arcane tools (dentist mirror) and purchase of an old stove points to 2, possibly related, outcomes: 1) You have come home. Welcome! In another 6-12 months you will be making new parts, sil-brazing (and understanding the linguistic as well as metallurgical elements of that statement), possibly building whole appliances for custom needs. Or fitting neatly into some other corner of this website. 2) Your meticulous assessment may be more precise than the factory. The 30 (ish) seconds with the compressed air priming should be fixed, but the time to "running well" will depend on the mass of the burners, the absorbtion (and radiation) of heat, and all those factors you are very familiar with from your career. With your stove's polished surfaces, it may also take your stove longer, which again you would expect. If it's the polish you should see that time come down. If it's your precision, it may not.
While in the 'lever up' position, do you notice the loss of pressure, and pump to compensate? And, do you pump to compensate after you drop the lever?
There is a slight, negligible loss of pressure to which yes, I do put pressure via pumping up the tank a bit. The second answer is yes.
Ok. Have you tried the spraying away from the case, like written above to test for spray/stream? Do this is a safe area away from flames. I was on my phone, sorry for the lack of details.
Right now the case handle and latch bail seem to stop the tank from engaging its hangers on each side fully up to their notches.
In the photo above, it's fully inserted as far as the tank will go. The notches are touching the stove case.
You could wrap some brass wire around the generator above the flame. I have a habit of tapping the generator, when hot, to dislodge impurities. It shows as sparks. I believe that helps the fuel flow.
