Hi, i have an issue with my petromax, the gap is supposed to be approx 14.2mm or more but i cant get past 13.6mm for some odd reason, it seems that the part that is holding the j tube in place near the mixing chamber is preventing it and im hesitant to bend it because it might break. It seems to burn "fine". It is pulsating a little bit, tried cleaning the nozzle but this did not help with pulsating. So what to do with with the gap and how much pulsating is considered normal?
Hi Parvis a few photographs are always helpful to help diagnose things especially with burner woes thanks edit : some members have found that adding fine brass mesh rolled into the vapouriser can help with pulsing
Hello A lot of lamps will flicker or pulse ; some more noticeably than others Not enough pressure will exacerbate things.. too little fuel also.. dirt (or dust) in the tank or dirty fuel Quite often the mesh is added when cleaning the vapouriser hasn’t made any difference? It may be best to try cleaning the vapouriser first as the loop part can clog over time?
I see.. that thin bracket stops any more adjustment I can’t advise you to bend it to get more adjustment.. but if it was mine then I would carefully bend it a bit I am sure I have seen this before but can’t find the thread @Parvis I have just found the thread and it seems that this is a common thing Other members have carefully bent the bracket to allow a little bit more adjustment on the j- tube also there is a great thread by @ROBBO55 where he fettles a Chinese petromax clone which I think you would find interesting feel free to search for it regards pb
I bought some brass mesh, its going to take few days until it arrives. Hopefully it fixes that pulsing.
@Parvis Notice how the section in the j-tube where the burner nozzle screws into has way more threads than you think it needs? That's there to adjust the slack of the j-tube to get your correct air gap. You loosen the nozzle with enough turns to provide the slack that you can elevate the J-tube higher when you keep the nozzle flushed against the bracket. Then set the clamp in place The nozzle remains in place by tension and friction of the bracket, Please do not bend the bracket as it's easy to snap.
Sometimes the threaded end of the J-tube is broken off. Due to use, heat or mall repair > twisted off. Then the adjustment or correct placement is not possible anymore. Adjustment is not done here but on the intake end (distance to the jet top). The J-tube is fixated by the bridge clamp on the inner hood. Mind you: there are J-tube screws out there which have a sharp point. It is easy to damage the tube with the fixating process which then give an other flow rate due to the dent....
As mentioned by @WimVe the sharp point damage the J-tube. I use my Dremel tool to ”unsharp” the screw, and then it works fine for me to hold the tube fastened in place. Regards Matti
Ther is always a way to get to 14.2 mm distance between nozzle and mixing tube. It's just a matter of technical creativity. E.g. bending the glass holder frame at the rod junctions, to enlarge the distance of bottom to top ring. Many more options possible, to achieve the needed result. Ps. typically, I tend towards 16-18mm
@Matti Kucer I use a metal bolt sized and tucked under the j-tube so it rests on it to achieve proper height. The screw on clamp now only has to be tight enough to keep the tube from wiggling which is alot more better than the crushing pressure to keep it elevated with risk of deformation.
Thanks for the answers, i still have not recieved my brass mesh. I also noticed a dent in the j-tube caused by the screw, its my fault for over tightening the screw... So i need to get a replacement part. Well live and learn
I assume that this is correct way to add the brass mesh? I dont know why but when i tested it, the needle gets bent, already 2 needles gone bad because of this... Im getting kinda frustrated with this
I think your roll is to small. Position is OK. The mesh should not influence the position of the rod. Which, in your case, results in a bend needle. (Best guess from a distance)
If add another layer of mesh, it gets kinda tight and the tube covering the mesh and fuel pipe wont go in place, there is 3 laps around that thinner tube
The original Petromax mesh : Mesh size: 60 mesh / 0.25 mm Wire thickness: 0.016 cm W x H x D (in cm): 12 x 0.01 x 6 How could you broke the needle? The needle must be removed first and assembled at the end. I took 9 x 6 cm for my HK500. (I have no 12 cm mesh) Removed the jet and the needle before. Didnt removed the rod. Rolled tight the mesh on drill 3.5 mm. Put on the rod and assembled the part with the loop. Assembled the needle and the jet. Works fine. Dimension took from there: Messinggaze Petromax Messing Gaze HK150 | HK250 | HK350 | HK500 und Geniol
I did remove the jet and needle first, i noticed that the rod where the needle is attached was slightly bent and was not in the centre, i managed to fix that by carefully straghtening it. Now the needle dosent break anymore. The pulsating seems to be much better now, next thing is to buy new j-tube and fixing the screw that holds it in place. Is it really that sensitive about that small dent in the j-tube? Thank you all for your help and tips, these lamps are still new to me.
I think, you cant move the j tube up to get the 14.2 mm gap because the mixing chamber (part 34) is stuck in steel bracket of top part 117. Try to completely remove/unscrew for a 1-2 revolves the mixing chamber, (also to straight the bracket) and try to set the gap. Reassemble the mixing chamber. As i see on your photo.
