Hi everyone. After trying to get an elderly relative covered up for the odd power outage I ended up owning a Petromax clone in the form of a Sea Anchor 909 (350CP rapid preheater). The build quality is poor to say the least but the lamp actually works if you don't mind that you have to close the preheater 2-3 times before it stops leaking or that the pump only pushes air if you really find the right angle As it turned out a few months later, the spare bits which came with the lamp also included a clearly marked 500CP jet and the corresponding needle so I will convert it to 500 and give it a go. What I don't know (as the Sea Anchor multi-tool lacks the spacer) is the height adjustment for the U-tube. Is anyone familiar with these lamps? What should be the distance between the jet and the bottom of the tube for 500CP? Thanks a lot.
Thanks Henry. I was presuming that the factory setting was right, as a matter of fact it was WAY off, due to the two cuts of the carburetor support not being cut high enough, therefore allowing it to wiggle back and forth and raise the end of the U tube considerably. After much grinding with the Dremel I was able to make the support stay flat and the minimum distance is down to 15.5mm. I will test and see how it goes
The petromax and clones standard gap for 350-500cp lanterns is 14mm. But with 15-16mm the work better. Some even need or improve further , if you increase the gap to 18mm or geometrical Max. E.g. at a worn out jet. The larger the gap, The better you can dim the light , by reducing pressure to 0.5bar or below.
Thanks, I'm waiting for my mantles to arrive in order to test. (the old one was destroyed when I was grinding the support). I'm at 15.5mm right now and the jet is brand new.
Before using the lantern check the cleaning needle tip for any form of a hook. They were usually cut off with no quality control. This could damage the jet fairly quickly but can be avoided by sanding the needle tip on a piece of flatting paper to rid it of the the said hook.
Thanks Andrew. By "hook" you mean that the tip of the cleaning needle would be slightly bent due to the cutting?
I haven't seen that (used 10x magnifying glass). However I have a different problem, the needle piece for 500CP appears to be a bit shorter then the one equipped on the lamp, so the cleaning needle doesn't come out of the jet at all. It goes flush with the top surface of the jet (tried from the top with the 350CP needle) but that's it.
@Adrian Your lantern will probably work but is best if the needle sticks out between 0.5 and 1.0mm. To make it do this, you must adjust the needle rod. If you need help, look here - Restoration of a PETROMAX 829 Lantern Click ENTER Rebuilding instructions, then scroll to chapter 5. You do not need to take the bottom part of the generator out of the tank. Henry.
Reaching out to the collective wisdom of the forum again The mantles finally arrived but at some 16mm air gap I still have a very large aura of orange burning fuel outside the mantle. The photo doesn't even capture the whole thing, it is clearly leaking flames up to the U-tube and the serpentine. It actually burns and produces light but to me it looks like it need a much larger air gap. The jet is brand new but with the Sea Anchor quality there's no guarantee it isn't oversized.
After taking the photo I bumped up the U tube by a good 2mm and the aura is now a bit smaller and way less orange but it is still there. I have another 2-3 mm of possible upward adjustment before the lower part of the U-tube is flush with the lip of the hole trough which it protrudes down.
~18mm air gap between the jet and the J-tube inlet is about the max that could help out on these problems. Above that, there isn't really much improvements to be had. Especially so if the root cause is a jet orifice being worn or too large. Do play about with the 'butterfly' mixer screw on the J-tube to find its optimum point. The vertical position is not always the best.
Thanks for the advice. I believe the problem lies with the poor adjustment of the needle, but I just cannot unscrew the top generator. The lower nut that should be welded on the fount (the one on which is screwed the bottom generator) is actually just screwed on this clone. Attempts to unscrew the top generator result in twisting the entire assembly. Is there any trick to be used? Or should I remove everything, weld the bottom nut on the fount and proceed from there? (just to b clear, I'm talking about the nut below the lead washer)
@Adrian : On my optimus I found a flat either side of of the "valve" body - I think a 15mm spanner worked. I then used a 14mm spanner on the nut half way up the generator. Undoing this will let you remove the top generator. Once you take out the "valve" shaft (connected to the control wheel) you should be able to lift the control rod out without distubing the lower part of the generator. Chris
If the entire assembly had already loosened, you might as well remove it and clamp in a vice while you work on the gland nut of the upper generator part. Otherwise, you could do it as described by @Fireexit1 . A 350cp lantern of these designs is basically almost identical to a 500cp, except for the jet and pricker needle dimensions. You should eventually succeed in this. Of course, there are some tough ones out there.
Nope, it hasn't loosened up, I twisted it back and it's not leaking even @3 BAR. Thanks for the encouragement, I'm almost there @chris: the problem is that on my clone the sides of the valve body are rounded. I suppose I could try to hold it there with a straight-jaws vise grip bud I'd only try that as a last resort. Maybe heating up the nut on the upper generator would lose it a bit?
French key, always handy Will give it a go and let you guys know how it went. The only caveat is that the clone has the center screw of dubious quality and with Philips head, will have to tackle it carefully to avoid striping it.
Well, Henry's suggestion worked like a charm, I managed to disassemble the upper gen, took the rod out, adjusted it to perfection... but no change The damn thing still has a clearly visible globe of otherwise nicely burning gas around the mantle, extending maybe 2cm in every direction. When shutting it down the copper u-tube is glowing red in the dark. Will try using the 350 jet that originally equipped the lamp and post here the result.
@Adrian Hi Adrian, Just a suggestion, I have a sea anchor clone that had the same terrible pump action, (getting the angle right to get it to work) very frustrating. I replaced the original with a leather cup from a vapalux lamp from fettlebox and it has solved the problem. I soaked it in oil and stretched it quite a bit to loosen it up and it seems ok now.
Thanks for the suggestion. I intend to get a car pump valve adapter for playing with the lamp in the back yard
Don't miss to have the matching 350cp cleaning needle fitted. Else your 350cp jet is ruined instantly. Check as well, if there is a gap between needle rod and the narrow passage in vapourizer, between lower and upper end of the Preston loop. If a gap exists, the petro bypasses the loop. Hence gas not hot enough. I experienced that in a Butterfly lantern. Aluminium foil around the rod closed the gap and improved the light/burn.
Thanks, that's definitely something to keep in mind. But in that case shouldn't the lantern be inoperable? (gas shooting up in liquid form and the lantern making big flames up the vent?) What were the symptoms in your Butterfly lantern? Mine still works and after heating up well the flames going out of the mantle are barely visible even if I stay very close.
@Adrian It would be ideal if the gap between the constriction and the rod be minimal. As to whether it'll flare-up with yellow flames or just a pale halo outside the mantle or burn satisfactorily would also depend on the condition of the jet orifice(new or slightly worn). There is a self-regulating effect once the vaporizer becomes sufficiently hot at a specific pressure. It'll reach an equilibrium point. Which means to say, the amount of fuel bypassing the loop section is limited by the flowrate of the fuel through the jet orifice once the vaporizer's overall temprature reaches normal operating levels because the heated fuel tend to expand in all directions, including towards the loop section and some back to the fount. The amount of fuel bypassing the loop is higher when the temperature is low and when the jet is really worn. There are kerosene-fueled lanterns that work with straight vaporizers without the Preston loop. It'll also help if the startup preheat be made a little longer and using a bulbous mantle to increase its proximity to the vaporizer in order to sustain sufficient heat. The effect of a loose pricker rod in the vaporizer's restricted section could be reduced by the conditions above. Of course, I've made my own pricker rod that's just below snug-fit in the vaporizer's restricted path.(just slightly smaller, similar to a needle through the jet).
I suppose there's no harm in rolling a bit of aluminum foil around the pricker rod and seeing if it still goes trough the constriction point. How do you make the foil stay where it should instead of being pushed up when inserting the rod? (or down if I install the upper gen with the rod already in place?) I was thinking about a bit of copper wire tying it below the constriction point then installing the upper gen with the rod in place.
Well, I took the plunge, straightened up as best as I could some aluminum foil from a chocolate bar, rolled it about 3 times tightly around the pricker rod and tied it on the lower end with some copper wire which I then used to make a spiral down the rod. No real change in the size of the flames protruding from the mantle but the light is whiter and the lantern is no longer pulsating. However the light output remains poor, here are some pictures I just took with the Petromax clone (using 500 jet and needle) near a relatively small butane lantern. The butane lantern has a matte glass, the Petromax is clear.
Btw, pics are taken with the Petromax clone at 3 bar. At 2 bar the light is clearly dimmer and almost orange when seen from 3 meters or so..
