Temperature at the top of the tank for Petromax 350

I've had to do that on two or three lanterns.

 

The height of the J-tube is adjustable by quite a large margin. If the generator, inner hood/burner assembly and j-tube is original to this lantern, there should be no problems.
Some clear pictures of the j-tube assembly on the burner relative to the position of the generator might help.

 

I cannot see the point in sand blasting the red enamel off and attempting to plate it, particularly if its not original. Even if you did, I doubt the surface quality would be very good. I think it would be far easier and probably a lot cheaper to find a genuine Petromax hood on eBay or one of the other auction sites.

Also, I'm very sure someone would purchase the hood with its red 'hat'. I certainly would!

 

On the first image we see that this is original petromax. The second picture shows that I have indeed raised the J-tube (the screw that adjusts the light is higher than the perimeter of the assembly). The third picture shows that the ring that holds the J-tube above the burner is already stretching upwards.

Now I re-measured the distance of nozzle to J-tube more carefully and it is 1.2cm. The distance for 350 (according to the petromax tool) should be 1.3. So I miss 1mm which is the missing 8th turn. But I wonder @MYN how did you say that it is adjustable by a large amount? It seems it isn't.

Either the 1.2cm is OK, or if not, I must either make the 8th turn or try to press the burner and J-tube further up if possible by 1mm.

 

I had been able to adjust the gap between the top of the jet to the j-tube inlet up to a near maximum of 18mm.
I usually set them in the 15mm +/-2mm range.
The usual norminal distance is around 13.2 to 13.5mm but this isn't a mandatory requirement.
If it isn't possible in your unit, you can also back out a couple of j -tube threads at the burner cap holder to get the additional 1mm. That's provided there is adequate threaded length at that section:

Another common occurence is that the metal stopper bracket is frequently bent. This might affect the distance of the gap.:

 

Yes, I've had to bend plenty of those internal metal brackets to get the J tube in the correct position. I guess its a common problem.

 

The distance is also depending on the wear of the jet.
So I would simply use the lantern as is. Test it maybe it will function 100%.

 

I did not know I could unscrew the burner cup without problems (there will not be any kind of leak there, right?). One turn should be enough to fix the distance. I will test the lamp as @WimVe suggests and if not working properly I will try to unscew the burner cup.

By the way @WimVe what do you mean by "wear of the jet" ? I have replaced the nozzle with a new one. What is the "jet"

 

Jet = nozzle

 

OK. The nozzle is new. So there is no wear issue.

 

Back on this lamp, after receiving parts and find time to install them I lighted it without a mantle to check that it works. Actually this is my first time I lighted a Pmax without a mantle. So I wonder is this picture correct? The flame around the burner is a clear blue flame but there is a downstream of flames in the center. Is this how it should burn without a mantle? I did not want to waste a mantle because it is not easy to get parts where I live.

 

Its working and almost there but still a little yellow. It should be more blueish. Reduce the fount pressure a little to see if the flame gets bluer.
Check that the jet is tight without leakage and the air gap. You can the air gap to get the best result.

 

Hm, OK I will recheck these points. Thanks.

 

I adjusted the gap. Now it looks right, yes?

 

Looks good to me, now it's time to fit a mantle and show us the results!

 

@Antonis Tsolomitis

That looks more like it, now for the mantle!

Regards, Jeremy

 

Yeap, waiting to receive 350CP mantles...