Petromax 829B is it original?

See if it remains lighted when you use a lower fount pressure.
Sometimes, it blows itself out if the air pressure is too high.

 

There's an atomizer under the nipple of the rapid torch, on it is a center hole where fuel enters and smaller holes around it for the air to atomize the fuel. These can get clogged, there is a pricking tool that usually comes with your purchase of your petromax, you use that to clean the jets on the torch.

 

Yes the two smaller holes under the atomiser cover are the usual suspects. They are very small and need a smaller pricker than normal stove ones.

 

The nut on top of the vaporiser is called the jet and a rather important piece.
You should really get familiar with how this type of lantern works.

Rapid problems are discussed here over and over.
A leaky vaporiser too, seal, rod lengths or jet or all of them.

You can and may ask ten or more problem question and you will get answers but do you then understand HOW the lantern works? In my eyes this is more value then getting quick solutions.

 

I have been fettling a 1938 Petromax with the rapid start. I used a very fine acupuncture needle (0.12mm) to clear those air holes.



Cheers

Tony

 

I double checked and cleared the holes again. The fuel hole was clogged, I missed it earlier.

Now I have a couple more problems.

The tank holds pressure without any leaks.

When I light the rapid, it leaks even though the rapid is burning.

When I open the valve to the needle down position, it leaks.

I did not replace the needle, but I do have a new one. Could that be the cause?

 

When the torch is opened and lighted, it 'consumes' a lot stored pressure by relieving both air and fuel at the same time. You'll see the needle of the pressure gauge indicating a rapid drop in pressure. That's normal.

 

Only leaks when needle is down or rapid is burning/open.

 

Are you saying it's normal for the lantern to leak some fuel when the rapid is burning? So not all the fuel that is being released is being burned.

What about the leaking when I turn the valve and put the needle in the down position? The lantern stays lit, but leaks a significant amount of fuel. Could the needle be worn out? I have not changed the needle, but it does not leak until I put the needle in the down/open position.

 

The leak is related to the main generator- somewhere above the foot valve. Make sure all is done up and sealing.nothing to do with the needle.

 

I'm going to check the spray pattern from the jet once it cools down. Since it only leaks when I open the valve, there might be a problem with the jet.

 

There is NO issue with the needle and/or spray pattern !
You should first and for all find and fix the leaks.
This all can be down without heating and lighting the lantern.

If your rapid connection on the tank leaks: seal it.
If your vaporiser connection on the tank leaks: seal it.
If your jet connection to the vaporiser leaks: seal it, that is check why it leaks because there is no seal there.
If your jet leaks from the needle hole: check foot valve seal and/or distances of the rods operating it.

As for lighting: HOW do you do this?

 

Lighting:
Pressurize to 2 bar, ignite rapid. Let burn for about 1 minute, open valve while rapid is lit. Close rapid.

I'm going to dunk the tank in water and see if anything leaks.

 

Check pressure indicator, with a gas lighter refilling can.

Remove filler cap/pressure indicator > hold the gas lighter pressure can in one hand firmly > press the can against the hol in bottom of filler cap > while doing so outside, check what pressure is indicating.

Gas light refilling gas cans have a pressure of 2bar.

Edit: mind you: some rapid's like a pressure under the 2bar indicator. It is and will be a delicate balance between pressure, hole diam., fuel and air temperature...

 

I don't have on of those, so that's not an option for now.

I did dunk the pressurized tank into water. I saw a leak at part #221 (rapid jet nozzle fitting), another leak at the pump cap, and another at the fuel cap pressure release. I alleviated all but the fuel cap pressure release. The leak is very slow there.

I noticed my needle is sticking out 1.5mm. When I installed it, I had it at .9mm. I will re adjust.

 

Could this carbon cause any issues?

 

No. That's not what I meant. I thought it was just the rapid drop in pressure shown on the indicator when you mentioned about the 'leak'.
So, it appears that the fuel is all over the fount when you're operating either one or both of the following:- the rapid or the pricker needle control wheel?
Just us check one at a time.
Say, let's start with the rapid preheater.
Remove the upper portion(frame, burner, hood and globe). Leave it like this:-

Pump up the lantern again to 1.5bar. Light the preheater torch. Observe the flame and where the leak actually is. It should appear clearer this way.
Then, shut the preheater and pump up to 2 bar or so. Observe and see if the leak continues or not. See what else is leaking too.
We should only proceed further once you get all leaks sorted out up to this stage.

 

@MYN
I stopped it leaking from the pre heater.

It's still leaking from somewhere in the valve/carburetor. It looks like it's coming from this nut. Does it need a washer? I put thread sealer on the threads, but it hasn't stopped the leak.

 

It's hard to tell though. I don't know how it could be leaking for there. It could be coming form higher up.

 

I'm going to use permatex high temp thread sealant on the jet nut. It can only withstand temperatures up to 400F. Is that enough?

 

There should not be any sealant of any kind in that place.
Try to look why it isn't air/fuel tight. It is metal on metal so surfaces must not damaged at al.
But the real reason is lower, like said many time by several people: the foot valve seal.

Mind you: some people use a tactic in which they fasten the jet more when it is hot.

 

I will check the foot valve seal next. Why would the foot valve seal cause it to leak when the needle is down?

I did replace the foot valve seal earlier.

It could be leaking from the lead valve seal on the fount. It's hard to tell, and I could see fuel leaking off the valve stem assemby.


This is how I screwed the lower part of the vaporizer assembly into the fount:

Removed old lead seal.

Screwed lower part in until it bottomed out, which was just over 7 turns.

Added lead washer.

Screwed lower part in 7 turns and clocked it. It can screw in a little further, but clocking would be wrong.

Did I do anything wrong in that sequence?

 

It's possible I installed the foot valve incorrectly. I'll post pictures of it once I have it apart again. I'm still waiting for it to cool.

 

I found the leak. It's coming from the valve stem nut. It looks like it's cracked and when I open the valve, fuel seeps out from the bottom of the nut.

 

I stopped the leak with an o ring, but now it's flaming like in the picture.

What could be causing this?

 

The lower half of my mantle has turned black, maybe that's what's causing the flaming.

Edited to add: the crack in the nut was only superficial, I'm not sure why it was leaking, but it looks like it will need to be replaced. An O ring is working for now.

 

Your J-tube dropped, likely from all the handling of the lantern during trouble shooting. Upsetting the air gap. Set it back to 14.2mm and tighten it, I've seen some people with more creative solution such as slipping a bolt under the bend, letting it rest on the brace to keep a more stable gap.

 

The nut is installed the wrong way around.The rounded part must press against the carburettor otherwise it cannot seal.
The part #107 eccentric fitting has changed over the years.Some are rounded on both sides and some are not.
If only one side is rounded then it should look like this.

 

Thank you, that was very helpful.

Does this filter need to remain in the B carburetor?

 

That brass mesh looks like someone added to keep the lantern from surging and pulsing (flickering). It slows the flow of fuel down so it can absorb more heat instead of acting like butter skittering across a hot skillet.

Considering it's the "gasoline" variant and assumed it had burned gasoline in the past, that added mesh is no surprise.