Petromax works after replacements, but needs tweaking?

Hello everybody, I recently bought a Petromax 829 500 CP. I completely unscrewed and took apart the lamp just to see and learn about it's techniques. I replaced some wearable parts and reassembled the lamp. At time of writing it's burning for an hour or so. Very bright light. But I had some problems with the ignition. See video. I learned that I really need to warm the lamp with to sets of spiritus before opening the hand wheel to light the lamp. But the hand wheel can't be opened fully or the lamp wil smoke and high flames appear around the top. Some tweaking with the hand wheel and now the lamp is burning very bright and hot, but any ideas on how to fix that hand wheel? I tweaked a lot and I am not a really handyman by nature. Maybe I broke or damaged something. I replaced the needle 2x.

 

Hi SulphurTX,

Did you check that you have the correct gap between the J tube and the nipple? Should be 14.2mm. Also make sure that you have no leaks - nipple, gas chamber, ceramic nozzle etc

The handwheel must be in the open postion when in operating condition otherwise you are using the needle to "regulate"the flow of fuel and will burn away.

No doubt the experts here will put you on the right track.

 

I'm sure @AHG has given you some good advice.

By the time you get the Petromax working in proper order, you'd likely become one.

On a properly working lantern, you should not need to adjust the wheel to find that 'sweet spot'. It should be turned 180° to get the cleaning needle to the 'fully-down' position.
If you've checked all the items mentioned and finding them to be in good order, then the jet/nipple orifice might be worn/enlarged. You'd then need to replace it.

 

I have the impression that the foot valve does not close properly.Either the spring is stuck in the valve or you have not installed the eccentric correctly.

 

I think the needle position (height) is not correct.
Besides the already mentioned options.

Without heating and inner burner assembly you should get a straight line of fuel from the jet.
Check this first with the height of the needle. The hand wheel should be able to turn around 360degrees.

Like Reinhard writes: if you haven't checked the correct distance of the two rows on the extender , you should do now.

 

Welcome aboard!

 

Thanks so much for all your advice. All the names of the parts you named I will try to translate and find and check.

When I check the handwheel without the carburator/generator screwed on it works fine. Needle down is arrow pointing downwards on the handwheel and needle up is arrow pointing upwards. But when the generator/carburator/vergasser is installed it acts strange. The needle sticks out about 0,5 mm. I read it has to be between 0.5 and 1 mm.

The distance between J-tube and nipple is correct. I will come back here with results!

 

What do you mean by extender and the rows? I'm so sorry, but all those names of the parts mentioned make me confused sometimes...

 

Ah I see : I mean rods.
And extender is the part that makes the rods go up/down. But maybe that is the wrong english word.

Picture 44-45 in the restoration doc.

 

Thanks. It stopped leaking fuel when handwheel is in up-position. The needle was a little damaged and I replaced it. We adjusted the rods a little.

Now there is a new problem. We get very high flames and an inferno when opening the handwheel. The clayburner is screwed tight but after a few minutes it gets loose and finally falls off. I already replaced it with a new one but that didn't solve the problem.

 

You can wrap a piece of mantle tie-string or a thin asbestos cord that has been thoroughly smeared with copper antiseize compound around the threads of the clay burner first. After that, hand-tighten it back to the mantle holder. Use 2 or 3 fills of the spirit dish to burn off the greasy constituent of the antiseize before actually lighting the lantern. The clay burner will have lesser tendency to loosen after that. Some guys prefer to use muffler or stove cement on the threads of the burner. I find it a little hard to remove in case I wanted to, on a later date.

Was it temporary only during startups? Did the flame settle out after a while or remained large and orange even after the lantern had been hot and operating?

 

The clayburner got loose and broke before I could get the lamp in operating temp and heat. I will order a new one. Is the metal clayburner a better option vs a real clayburner?

 

No not really. Sure you can screw it in really tight without breaking it but brass and steel expand at different rates and after a while it's possible the burner will come loose.

@MYN gives good advice about using spare mantle string and copper antiseize compound / muffler or stove cement on the threads of the burner.

 

I will try the cement! Bought a pack of Holts Gun Gum and will order a new clayburner... To be continued!

 

Tried another clay burner and holder, but still the same problem with high flames burning in the top of lamp. It seems something is going wrong with the amount of fuel/air. Tried the small screw and checked the 15mm J-tube to needle distance. Any ideas? We already checked the whole lamp and parts. It didn't leak petroleum yesterday when on full pressure of 2 bar when the handwheel was closed. See video of the actual situation

 

Good effort ! - love the video. I think you are nearly there but the way you are lighting is not correct. By the time you have pumped it up it has cooled down too much
A few pointers:
Make sure that the jet (nipple) is done up tight (there may be some fuel escaping up the threads)
Pump it up to 2 bar before you do the pre-heating, with the valve closed (pointing up)
The inner cap does not seem to be sitting properly - it should be very flush - this will change the gap between the cap and the jet.
The top cap should be in place as it does seem to change the burn a little

the mantle should clear up once it is burning properly.

you are nearly there

 

Thanks, will try your tips! I saw multiple videos where someone uses this slow lighting procedure. I also tried the method you mentioned earlier and I got a nice light. So maybe the lamp is not hot enough after 4-5 min of heating with spiritus? And it needs the heat of the mantle to heat up more... Will try tomorrow and share the new video!

 

The nipple is not screwed in properly. I see lots of fuel & flames at the seat, causing a rich & sooty burn. Besides this, the gap to the mixing tube is way too small, and the inner chimney is not positioned properly. And third, the preheating does seem to be insufficient. Placing the hood on top during preheating will get more heat to the top of the vaporizer.

 

Thank, will try tonight. The gap to the mixing tube is 14,2 mm. That's too small? What do you mean by the inner chimney?

 

@SulphurTX

hi there.. the inner chimney is This part..



..it has to sit properly on the frame



This is the outer chimney or hood
It is important to have it fitted especially outside as it helps to keep the lantern temperature nice and hot

if the Inner Chimney is not fitted correctly it affects the way the fuel enters the mixing tube and it affects how much air is drawn in?

 

This is how it should sit



Nice and level
This next picture shows it sitting too high?



I think @Fireexit1 and @Martin K. were worried that this was not sitting properly in your video?
Also the outer chimney or hood has to be fitted outside

On some lanterns the Inner Chimney is a tighter fit than the one I have shown so more care needs to be taken

mid it won’t sit in the top of the frame/cage then it needs to be looked at more closely?

hope all that helps
Regards
pb

 

Excellent PB - and once the inner is sitting correctly the gap is between 14-18mm - worn jets need a slightly larger gap - but that is fine adjustment

 

Hope it ‘reads’ properly .. lots of different languages.. different interpretations sometimes

I haven’t watched the video as the phone won’t let me.. Martin said about the nipple being loose?

thanks Chris

 

You're right. The inner chimney is not fitting in right and smooth like the pictures you send me. I can't exactly find out why, but I will take a look at it tonight. I will let you know and make a new video or photo to show the situation.

 

Here is an older Petromax and it is a more exact fit than the other lantern I grabbed
The Inner Chimney has cut outs that sit over the square parts on the frame/cage.. make sure it isn’t catching on either of them







another indicator that it is sitting properly is how far the nozzle/jet sits



Check to see it is not catching on anything

You must try lighting it with the outer chimney or hood sitting in place .. like others have already said it helps it preheat and to burn as it should.
If it looks like it won’t sit properly then the inner chimney is still too high?



the only other thing i can think is if the glass is too high? Is it marked Petromax?

 

Some better pictures of my Petromax, inner and outer chimney and the glass. I can get it in place but it's not a perfect fit. I have to push and pull a bit to get the inner chimney in place. The glass is a little loose in the cage and it's not marker Petromax, but Schott Suprax.

 

And a new video for better views on the chimneys and glass...

 

Ok, the glass is not too high

you are sure the Inner Chimney is in the correct position

I would do what others have already said.. alter the air/fuel mixture

have a look at this gap on your lantern



The original setting was 14mm from the top of the nozzle/jet to the bottom of the mixing tube or U bend

if you don’t have callipers you could cut a piece of card but FIRST try and measure what distance you have Before moving anything

Post here to let us know the distance??

 

Is doesn't fit anymore... I pressed the inner chimney more down into the lantern body. It wasn't placed properly as some of you noticed. So the distance between the nozzle and the opening of the J-tube is nos less than 14 mm. I will correct it tonight and light the lamp again! And preheat is as you already mentioned before... Will be continued!

 

Thanks for getting back

looks like the inner chimney was too high?

Fingers crossed/touching wood for laters