Upper Carburetor Leaking

Hello all from Istanbul.

I noticed an interesting thing with my HK350 when I lighted it up this evening. There's a very small leak on the upper part of the carburetor (152) visible in the photos below, and it gives away a small flame about the size which would come from a lighter. Doesn't cause a significant pressure loss. I have a spare upper carburetor and I'm not worried about this too much, but I was quite surprised to see it. Has anyone encountered anything similar, and if so is there a way to fix it? I'm not aware of any spot weld which can withstand such heat, certainly not solder, but perhaps someone has experienced a similar issue before.

My second problem is the top part catching fire practically on every attempt out of two. I follow the advises I read on this site, heat up the whole lamp with at least two cups full of alcohol (approximately 6-7 minutes) then gently turn on the lever, but for some reason it goes up in flames and soots up the whole top group. I'd appreciate any tips you might give on this, there's obviously something I'm missing but haven't solved it yet.

Many thanks in advance,

Best, Kerem

Hi again, just a small addition; the lamp is still running, pressure below one atmosphere and the flame is gone. So I'm assuming this has to do with high pressure, I started the lamp on a pressure just a hairline above 2 atm., and the flame was at the size of the first photos. Around one atmosphere it became smaller and now below one atmosphere it's not there. I guess this is an extremely small puncture expanding with heat and letting out the gas under high pressure...

Hi Andy, appreciate the response.

I'm suspecting the brass mixing chamber, because it screws on very easily to the J mixing tube. Couple of times when I tried to tighten it, it even went through and passed onto the unthreaded parts of the J tube. So ordering a new mixing tube and a chamber is on my list. But I'm still not sure whether this is the problem, as I hold up the chamber straight against a strong light source and I don't see any gaps between the chamber and the J tube. But perhaps the hot gas does escape through, even though there's nothing for the bare eye to see.

I think I can rule out the first points you made, as I have checked the nozzle tightness and I do get a fresh, healthy jet of spray straight up to the mixing tube when cold. The distance between the nozzle and the J tube is also more than 14 mm, as I've read some tips about increasing the gap here in this forum and experienced better results by doing so. I'll try to focus on making the mixing chamber fit tighter onto the J tube...

Many thanks!

Hi,

Thought I'd update on how it went with the 'soft start' this evening. I realized what my mistake was in the previous attempts; the pricker control wheel would be up and I would build up some minimal pressure in the tank, something like 5-7 strokes. Then after burning two or sometimes even three cups I'd gently rotate the wheel downwards, and half of the time it would start and the other half it would go up in flames.

Now after Andy's advise, I started with a full fount with no pressure, pressure release screw open, pricker control wheel down, pre-heated with two cups of alcohol, and when the second cup was nearly finished I closed the air screw and started pumping slowly........ And it lit up like magic

Thanks for the tip Andy. I even haven't attended to the mixing chamber and the J tube yet, seeing that the problems were in the preliminary steps I was taking. Probably nothing even wrong with the connection of the chamber and the J tube...

Now if you'll excuse me, I'm planning on sipping a nice black coffee beneath the lovely warm yellow light of my Petromax

Have a nice evening all.

Kerem

Okay, one more thing which you could help me with... Mantle breaks (rips, falls down) during pumping... This is probably due to the jostling and shaking during each pump action. This already happened twice before. Anything you could recommend?

I'm happy with my pump and leather, but is it maybe too stiff, meaning that the spring at the lower end of the valve is too hard?