Distance between generator nozzle and mixing chamber on 250CP Petromax

Hello. Writing once again in hopes that someone may tell me the correct distance between the generator nozzle and mixing chamber for a Petromax 250CP, please.

Thank you in advance for your time and assistance.

 

All dimensions can be found here: http://petromax.nl/PX_tabel.html

 

Any distance above 12mm up to mechanic maximum. Test&trial.

 

@WimVe Thank you very much!
@bp4willi - Thanks!

 

Set the distance at 12mm (wasn't far off), but the difference was substantial - was burning orange with constant flame, but now glowing bright white, as desired! Many thanks, Danke

 

Follow up to previous post, please:

I have noticed that my Petromax 250CP burns bright white after setting the correct 12mm distance. Strange is that I put the ventilator on the lantern and the light changes from bright white to an orange fire around the mantle. I remove the ventilator and flame returns to bright white.

Any ideas? Thank you!

 

Increase the gap to 14-15mm.
Possibly the hood doesn't shut off the exhaust side from the air intake side.
I once had a 500cp lantern , in which I had to extend the rim of the inner hood via aluminium adhesive tape, to close the gap towards the upper hood.

 

Thank you @bp4willi. I moved the mixing chamber to maximum distance (between 14 and 15mm) on my Petromax 250CP. Unfortunately no change -

 

I would like to see the J-tube with the small set screw.

 

Some pictures of the whole lantern may help also.
Something is wrong with the air flow.

 

Hello and thank you for responding - much appreciated. I've attached photos as requested.

Please know the following:
J-Tube (mixing chamber) distance has been at maximum, middle, and minimum distance, all with no change. The lantern burns bright white (as desired) without the outer ventilator attached, but burns red/orange/black with large flames when the outside ventilator is attached.
The Mixing chamber screw for the paddle is vertical, as in photos.
Changed the needle (new needle), and I have tried many different distances for the needle relative to the nozzle (jet).
I have changed the nozzle/jet (new), I use Kerosene fuel, and Petromax Superior Quality 500 mantles.

Of note - the fuel from the nozzle comes out at an angle (see photos), but the kerosene still arrives in the mixing chamber.

I'm very happy the lantern burns as desired (even without the ventilator attached). This is my first full restoration of a Petromax, so my expectations are not high!

Thank you again for your kind advice.

 

Hi - how very odd. Well it does need to throw the fuel more or less directly upwards. I am wondering if the needle is not dropping fully away from the jet. Some of the aftermarket needles are longer than the originals. If the needle is not fully retracting from the jet then it may well throw things off course. Once the preheat is done it will be gas when it comes out, but lots of orange flames means liquid coming out normally.
Also - how much pressure are you using ?

 

Hello in Brighton, and thank you!

I raised and lowered the needle, but without change in results. Currently I set the needle so that it barely breaks the surface of the jet.

I do preheat, and the fuel does vaporize, but as you say, if it burns with orange flames it must be liquid.

Regarding pressure - 2 bar (up to the red indicator on the manometer).

Thank you again for your thoughts.

 

Well you can prove it is not the needle by running it without one. Another thought is that you may have a small crack on the generator that allows fuel to escape. Worth a careful look? Also maybe switch the jet back and see if it also goes sideways?

 

The fuel stream to me makes the impression that the jet is worn. Try to use a new one and a new needle which is properly rounded at the top. Some of the new needles are simply pinched off with pliers and have sharp burrs that destroy the nozzle.

 

Was that before or after you took this image which clearly shows the air gap is only 8.5mm ?


Cut a piece of card or use a half inch (=12.5mm) drill bit to measure the gap between the two points indicated.

 

With the hood still in place and lantern still operating with the dim, orange glow, try to peek and observe the J-tube.
Sometimes, it will glow red when you put on the hood. If this was case, it will cause the mantle to glow dimly because oxygen being used up by the burning inside the J-tube.
When this happens, the only easy way to resolve that is to replace the J-tube.

 

Many many thanks to all of your kind support. Since the last post, I moved the mixing chamber/J tube back to 12mm, but all else unchanged (had a new needle, new jet already). I lighted the lantern this evening, burning bright white --> put the ventilator on. Burning bright white WITH the ventilator. Only other change is that there is absolutely NO WIND this evening whereas previous burns was in moderately windy whether.

Again, I thank you all for your generous contributions. Feels great to finally burn this beautiful PMax 250 properly!

Thanks!

 

Kicking myself here for not realising you are missing the globe (glass) - this is important as you now know it stops the wind messing up a) the flame b) the pre-heat c) the airflow and lastly d) stops insects crashing into your mantle and breaking it.
Now you know it works you should invest in one !

 

@Fireexit1 , you are right, next time we have to ask if globe is mounted, besides the pictures.

 

Thanks guys. I've got years of experience with Coleman lanterns, and I've never had a problem like this. Colemans run the same with/without the globe. These Petromax are a bit more fussy!

Thank you again!

 

Would love to purhase some 250-sized globes, but have not been able to locate them here in the US. I reached out to some of the links provided by members, including:
base-camp.co.uk

Was unsuccessful location this globe. Any advice is welcomed.

 

I guess you missed item 74/2 Glass Chimney 250cp, no logo

Have another look about halfway down this page - Petromax Spares Price List

 

Overlooked. Thank you again!

 

Congratulations for getting the Petromax issues resolved @hansblix1.
For the glass globe, besides Basecamp in the UK, there are also a number of sellers elsewhere. How about Thailand for some repros?:
petromax 250cp glass globe walmart - Google Search

I've not bought anything from the above source but you can also check if it is any good.

 

Thank you very much @MYN. Everyone here gave me the directions for success.

Oh I've looked high and low for the 250 globes - 350/500CP are available, as you searched above. I'm making some progress with some contacts here in the US and in the UK with help from @Henry Plews.

Thank you very much for your thoughts.

 

As for the gobe: I would go for one with the brand Petromax and logo G or E&G on it.

 

This is a Hipolito H-202.It was manufactured in Portugal from around the mid-70s to probably the late 1990s. All 250 cp lamps made in Portugal from this period had a paddle on the regulating screw #32 that was too thick for the norrow J-tube #33 .That's why these 250 cp lamps were hot and dark. The only solution is to remove the regulating screw #32 ,file it narrower and reinstall. The result will make you happy.

 

Oops I forgot that. So find a Hipolito marked globe.
Which I must admit can't remember having seen recently.

 

Thank you very much, @Reinhard. I will try this also. I have been impressed by the results so far, but if excellence is within reach, let's try for excellence! Thank you again!