Hello everyone! I am George from Greece and I collect Kerosene and Gasoline pressure lamps and stoves since I was a kid (now I am a big boy! lol) Here is my new to me Optimus 930 300cp bought some weeks ago from a retired man. The lantern lit just a few times in the past and looked like NOS so everyone will agree that worth the 50 euro. Well, it came to me with some dust and realy aged kero in the tank. The kero looked like a gum so i started to disasemble every single part to clean it properly. After the cleaning procces I reasembled every single piece with precision and extra care (yes, I am a mashinist). Filled with kerosene and lit it. Everything looked perfect during the first hour, when the light output started dimming and dimming. Black mantle came after two hours... So I tried to prick the nipple as I rarely do with my German Petromax 500cp and the light output regained again. The phenomenon came again after an hour and so on. I realized that when the light output drops a thin and vertical carbon "needle" builds on the topof nipple hole. The pricker removes it and it comes again after a while. The kero is one year old but stored in a plastic container suitable for fuel. Any suggestions please?
Check the fount and make sure it’s clean. Stuff can build up in the fount especially if it’s been setting for any length of time.
Hi George, The found the vapourizer and the bottom vapourizer part are in perfect clean condition without rust, dust or humidly. Here are some photos of the carbon buildup on the nipple hole:
Welcome aboard! Residue from the old fuel has probably stuck to the inside walls of the tank and when fresh fuel has been put into the tank the residue has gradually loosened and polluted the fresh fuel, the usual cure is to put some ball bearings into the tank and then give it the shake rattle and roll treatment, then pour out the fuel and ball bearings into a container and check how much dirt is in the fuel. Then clean the ball bearings and put them and some fresh fuel into the tank and do the treatment again and continue to repeat this procedure until the fuel comes out clean. The Optimus 930 lanterns sometimes over heat and that can cause problems such as back burn and if that happens there is also a very loud roar from the lantern. Fount is another name for the tank.
Welcome to CPL @Georgelap It's hard to get all the contaminants out of the loop on the vapouriser. Even when you use a piece of stranded cable to dislodge the carbon. Small particles can work their way through the system and build up in the jet. Run the lantern using the pricker when necessary. It often settles down after a tank or two of fuel is used. It could also help to flush everything in situ. Remove the nipple (jet) and pump a tank of fuel through the system. This can dislodge any loose particles.
Looks more to me as if some kind of residues in the tank has been resolved by the fresh fuel and polluted the vapourizer and jet. Even a small amount of deteriorated fuel can lead to great annoyance because the stuff will gum up in almost no time. That's how it looked after a short while of burning some odd smelling kerosene in my 351L. It wasn't that easy to clean out the vapourizer. Had to heat and quench it quite a bit in order to get it clean again.
Have had this with a Primus stove (silent type) and it was definitely the fuel. Made little carbon whiskers around the exit of the jet. New fuel was all that was required. It was a certain type of prepack paraffin which I will no longer use.
Maybe the problem is the old fuel. It is weird because I run my petromax with the same old kerosene without any problems so far. Does anybody know the nominal diameters of the nipple and the needles of optimus lanterns?
I cleaned the tank with some steel balls and the vapourizer with a blow torch and compressed air. The whole lantern is in perfect clean condition so I am sure there are no any particles in the system.
Its a 300/350cp lantern. The nipple/jet orifice should be around 0.19~0.2mm. The cleaning needles would be 0.01mm smaller in diametre. You can easily just test it out with new kerosene to see if the fuel's the issue. There can be a variety of reasons for the symptoms you had described. An occasional speck of dirt or carbon partially blocking the orifice can be one but that can be repeatedly cleared by operating the pricker needle. The blackened would clear up after a while. Test this without shutting down the lantern. If the sooting continues or worsens, it is then not merely the fault of the occasional blockage. Enlarged or worn jet orifices are another common cause. Replace it if available. Otherwise, you can carefully peen it to reduce the diametre. Another likely cause would be that the lantern isn't able to continuously sustain sufficient vaporization. For this, it might look ok upon startup but the gets dimmer as time rolls. It can be related to a worn jet but it can also be due to thick coke build-up inside the Preston loop, causing poor heat transfer. As mentioned, its not that easy to get everything out just by mechanical means or heat-quench cycles. One of the ways I use to completely clear it is to first block out the inner restriction inside the loop with heat-resistant material like ceramic fibre or asbestos. With both ends of the vaporizer opened, gently heat it with a propane or lpg torch till its dull red. This is followed by blowing pure oxygen into the lower opening of the vaporizer using an oxy-acetyene welding torch. Yes, I do have oxy-fuel equipment at home. If there are any remaing carbon in the vaporizer, it will intense combust, turning the section brighter than dull red. I would carefully control both the propane torch heat source and the oxygen entry, so that the carbon burn out procedures don't end up with me melting, burning through or distorting the vaporizers. This way, I'm usually able to completely clear out all carbon deposits which, isn't always possible by heat-quench or mechanical wires alone.
Thank you all for the replies! Just bought a can of fresh kerosene and the problem disappeared. Where do you buy parts for classic optimus lanterns? I tried to send some emails to Fogas.se because they seem to have plenty of these parts but no one answered...
