Hiss at top of lamp + question about seal tilt lever rapid heater after rebuild

Etmnidj · 10. Mai 2020

Hello,

Last days I dismantled a Petromax 500;polished it and replaced all lead seals, I did this for the first time, so it was quite an adventure...... Today I rebuild it, the carburetor lead seal was leaking at first start-up, so I had to replace that one once again. I saw a video on Youtube in which they said the carburettor needs 7-8 rotations and than it would be tight enough, so I did that, I found out that in my case it was 9. Also depends on the thickness of the lead seal of course.

After replacing the leaking carburettor lead seal, I pressurized it; it held good pressure, also after 2 hours and no leaks.

At the second start-up the lamp burnt well, although I have a few questions:

1. The rapid burner leaks only at start-up, not during the 2 hour pressure test; I suspect the rubber seal on the kliphebel, it looks a bit deformed? You can remove it by untighting the screw; but I cannot find a replacement loose rubber seal; only a complete Kliphebel (223). Any other suggestions what the leak could cause? I checked the lead seal of the rapid burner with leak finding spray, but no air bubbles what so ever.

2. After the lamp burnt for some time I shut it off, and pressurized it again to check the rapid burner on leaks. I noticed a hissing sound from the top of the lamp,that sound was not there when the lamp 's was pressurized for 2 hours .... Can it be caused by the fact that the carburettor was heated, I suspect the needle on top of the carburettor, but it's looks like its not leaking fuel from there.... Any suggestions, replacing the 'needle"? I have a spare...

Thanks in advance for your answers....

Regards Niels

pfalzbrenner · 10. Mai 2020

Hi Niels,

1. the little rubber to seal the rapid is available as part no. 229 - see e.g.

"Fassung mit Dichtung & Schraube HK150/HK250/HK350/HK500"

https://www.pelam.de/de/fassun…50-hk250-hk350-hk500.html

no need to buy a complete Kipphebel.

replacing it is a piece of cake if you have a tiny screwdriver.

2. That hissing sound needs more info - how did you turn off the lamp ? you should open the manometer screw to unpressurize, then any hissing will be very unlikely

Edit: I needed to re-read your post to fully understand. I would estimate that the shut-off valve at the bottom of the carburetor is not sealing 100%, but that may not be drastic - use softstart with alcohol, then there is no need for it at all.

It could be that the inner rod of the carburetor is extending a bit if the lamp is hot, opening that valve a bit (despite valve closed - regulator wheel nose "up"). If the lamp is lighted, it is needing that for fuel provisioning anyway (wheel nose pointing down), and the "hiss" is the normal operation sound.

To get rid of this , you head for

- dismantling carburetor

- fit a new shut-off valve

- maybe also adjust inner carburetor rod

- new lead seal for carb.

Edit 2:

The needle is *not* meant to be any kind of sealing/closing for fuel or air flow (of course, it reduces the diameter of the boring when up a bit - but not really tight).

As long as it is protruding cleanly through the jet valve when regulator is closed (nose up), there is no point in changing it.

Etmnidj · 10. Mai 2020

Thanks Pfalzbrenner,

I shut the lamp down by opening the manometer screw, I learned this from this Forum

Pressurized the lamp this evening and the hissing sound was not there, I didn't fire it up, so the lamp was cold, I'll give it a try somewhere this week to see whether it's there when the lamp is hot. I'll report back after I've tested it.

Regards Niels

pfalzbrenner · 10. Mai 2020

Hi Niels,

I understand your interest in accuracy to test the lamp thoroughly - however, it never came to my mind to do what you are trying :-).

If the lamp is keeping pressure and not leaking from the top nozzle / jet when cold (and pressurized), all is fine. You should not store the lamp pressurized - chances are, you'll have a mess of spilled fuel for a lot of possible reasons.

I use my lamps , "unblow" them after use, and only check for leakage next use - of course, always ready for a quick release(of pressure) if something is leaking.

best,

/Matt.