I got my first 111T last year. It arrived in decent shape and fired up without much trouble. When going flat out there was a nice blue flame: However when throttled back there was a consistent yellow flame around one half of the outer cap’s circumference: The flame starts well, but turns yellow after a few moments so I suspect there is a leak that only manifests once things warm up. The good performance when throttled up suggests to me the leak is a minor one. I put the stove away to revisit once I had gained a bit more fettling experience and took it out again recently to see what I can do. I have cleaned the burner but can’t find any evidence of a leak. No wisps of white vapour. No damp patches as the burner cools. I even resorted to putting purple dyed methylated spirits in the tank, pressurising it and leaving it dusted with icing sugar overnight: but there were no purple smudges the next day. There are what look to me like signs of an earlier repair: I am loathe to crack out the MAPP torch until I know what I need to fix. Does anybody have any suggestions that might help identify the leak? If I can’t pin it down is fluxing and heating the existing silver solder around the tubes to get it to flow a viable course of action? Can I ‘top up’ with fresh (low silver / medium-hard) solder? Or am I better trying to remove the old stuff? I will bring the stove to Newark next month if anybody wants to cast an expert eye over it. -R
Hi @kerophile - I’m familiar with this thread, it got me started on fixing up another 111T last year (Pinhole leaks in 111T burner). Both threads have a clear pointer to the leak - a dampness around the spigot. I don’t have that here. If I can’t pin down the leak I’ll probably follow your lead and silver braze the join around the spigot as very likely culprit. -R
Yes, that’s what I think is happening here. I can’t think of any other way to try and identify the leak (I’ve tried the dunk test as well). Without that knowledge I think all I can do is fill the join around the spigot and see if that solves the problem, if not, then I need to tackle the joints underneath the burner and the existing work that appears to have been done there. -R
@IRM I am not any kind of an expert but I get something similar with a couple of silent cap type stoves and have noticed that the orientation and the position of the caps sometimes change the burning angle (lack of a better word) and will get longer blue flames on one side vs the other and in other cases yellow flames like you are showing. I get something like a screwdriver and gently push the caps around while the burner is lit. There is a slight bit of room for the caps to move on the burner, and if they are not perfectly fit they always do this. This has happened to me with: 2 Phoebus 625's (original caps and others) - White Gas 2 Shmel stoves (1 and a 4) - White Gas Primus 1 with silent cap - Kerosene I have roarer burners for all, and when switched the yellow absolutely vanishes. My solution is to try caps until I get a set that works really well on that stove, or push the caps around until the yellow goes away. Sometimes the caps are not perfectly round and with a not perfectly round outer cap and a perfectly round inner cap there is a variance in the flames. I measure the caps to be sure I am not crazy and they will have some differences on width from across the radius. (X and Y) maybe something to look at, but I have seen that on a few of my stoves before (yellow flame on just a side)
Like this... Pushed caps until flame is blue on all sides and flames are same length Crooked caps (flames shorter on the right side and will start turning yellow in that area) To confirm that the caps are loose...I take the caps and put them together in my hand like they are when installed on the stove. I see if I can move the inner cap from side to side inside the outer cap. If I see that I know I will put the outer cap on the stove burner by itself and see if I can push the cap side to side and see if it moves there also. If it moves in both places then when its burning it will change the flames like I described and burn yellow unless they are straight. Just an idea....but if I saw when you are showing I would think its the caps.
@IRM burn the stove for a while up when the yellow flame appears. Then remove the caps and stop the combustion. If hot flammable vapor leaks somewhere, with a torch, try to identify the leaking point around the joints. If there is a vapor leak the torch will ignite it and you will see where it is if there. Did you try another jet to see if this behavior persists? Nicola
@Nicola Francesco Elia yeah that makes sense too... But if it was off then there wouldn't be anything to leak (unless the valve is faulty)?
Well yes you are right, the test can be made also with valve open… also if in practice the valve closes the stream before the jet, so the mixing chamber around spigot should have vapor inside.
Ooooooooooooooooooooooooohhhhhhhhhhh......I can see that too. Just adding more to my mental library now! @Nicola Francesco Elia Yeah if he had that I would think he would get a lot of underburn too..
I closed a jet by soldereing it shut. Then install, heat the burner with a torch and open the valv. If there is a crack that has opened as the burner now is hot, it will clearly show were it needs to be fixe
@Remus1956 I’m pretty sure the caps that came with stove are correct. The yellow flame is always on the same side regardless of how I place the caps. They fit snuggly and are held in place by two tabs on the burner: That said, I’ve just tried adjusting the outer cap slightly whilst lit. When I raise it a fraction on the yellow side the flame turns blue (raise it too much and I get underburn), but I’m wondering if this is a result of more air being available for the combustion to balance the surplus fuel from the leak. @Nicola Francesco Elia I’ve removed the caps when hot a few times to look for vapour without success. I’ve tried your suggestion and run a small flame over the top and saw no orange, but I will give it another few attempts. @tretrop that’s an interesting idea. Similar to what @Nicola Francesco Elia suggests, but a bit more… forceful. I will have a think about what’s involved and may well try it if other approaches don’t produce a result. -R
@IRM the original inner cap should be with holes on top (matching the spigot with holes). Is it like that? Check the vertical axis of the burner. It seems that more vapor goes to one side producing the richer flame. I don’t think there is a leak otherwise it would probably underburn. Pressurize and open the burner valve when cold, without caps, to see if the stream of fuel is perfectly centered in the spigot or if you notice something wrong. Nicola
@IRM its the same with the Phoebus and Shmel stoves...they have tabs and the caps have cutouts. They still move from side to side on my examples. AHA...I had the same thing with the height of the cap on one set. I found that they were not perfectly flat, and the on one side 3 out of 4 rows burned (blue flames out of the burner holes) and the opposite had 4 out of 4 burning. I can see sometimes a sliver of flame where I gently lifted the cap. Not that I know how to fix it, luckily on mine I have a bunch of the caps and switched them all around until I got good burning sets for the stoves. Funny...1 phoebus doesnt like the original phoebus caps, but korean aftermarket caps. The other phoebus runs like a dream on anything and runs best on the phoebus caps. as I said...not sure...but it might not be a leak in the burner, could be the caps. Adjusting the caps shouldnt affect the yellow flames from a leaking burner in my opinion as @Nicola Francesco Elia stated I agree...could also be a bad jet shooting the fuel richer on one side than the other...had that happen too.
I would try without the needle, then a new jet and then a new burner cap, before I start soldering. I recently installed a new (like shiny, right out of the bag new) original Optimus cap on one of my Explorer 11's (Cobra burner) and had problems with underburn and half the cap glowing intensly at "half speed". At full throttle or very low simmer, everything was normal. I put on the old cap and everything was back to normal. Kind regards Tron
The inner and outer caps match (holes around the top of the inner). I have swapped caps with another 111T and see the same orange in the same position and I’m on my second, possibly third jet. I have found what appears to be a small leak at the base of the burner, there is a very small seeping of fuel, but I don’t think it’s causing the poor burn. @Nicola Francesco Elia you may be onto something with regard to vertical alignment, the stream of fuel leans a little towards the area that’s burning orange: and it may be my imagination, but when throttled up the flame pattern on that side looks to be a little larger than the other side: Is this of a skew to be the cause? If so, how do I remedy it? -R
@IRM well, that explains everything, the jet stream looks really unbalanced to one side. You said you have tried different jets already (that often are the cause), so in your case probably the burner is a little out of its original geometry, bent probably on the side longer tubes… Solution is to fix the geometry back bending the burner in a bench vise… no instructions available, so up to you to heat bend and make a stream test to see the progress… Bending obviously is an operation that can lead to cracks at brazed joints, but that’s is anyway fixable if happens… Nicola
