I'm pulling apart a very sooty Optimus No. 99. It had unleaded gasoline in the tank, and was a complete carbon-covered stinking mess. It had obviously caught fire at some stage, and the person that sold it cleaned the loose soot off to expose some of the brass, but that was all. What surprised me was what is seen in the photo below - encrusted carbon on the control spindle and pricker rack. The fire was inside the burner! It's all salvageable, and I think I've worked out what happened, but I need to do a few more forensic investigations. I'll keep the rest of the fettle on this thread. Cheers Tony
I wonder if just used with only leaded fuel for its life or anything that would burn, stuff that does not burn thoroughly? Duane
Hi @Tony Press . You do not need to have direct combustion to get carbon deposits. Heating petroleum mixures in tubes, retorts, and burners can result in "cracking" of the hydrocarbon mixture with the more volatile compounds separating off leaving the tarry, sooty, heavier fractions adhering to all the internal surfaces. As you will know, clearing these hard, adherent, and relatively inert deposits from well-used burners is quite a task, and sometimes burning them off in the presence of excess oxygen is the favoured option. It seems possible that your stove burner was well choked with petroleum coke deposits, perhaps through the use of dubious fuel, before the stove caught fire. I am sure that with your fettling skills the stove will soon be back in full operation. Best Regards, Kerophile.
@kerophile Yes! Of course you are right: no internal fire but the combustion of dubious fuel causing a build up of carbon inside. I've seen plenty of carbon build up in standard roarer and silent burners but never in this kind, especially inside the spindle chamber. The carbon/plus-other-residue had actually formed small crystals. The culprit in this case appears to be bad fuel (automobile unleaded gasoline) and a partially disintegrated wick. Either the wick, or the carbon build up, or both, blocked the fuel flow at the end of the fuel line before it entered the upright part of the burner. I expect that's what caused the fire with fuel escaping somewhere (filler cap or NRV?) and the whole thing up in flames. The wick was stuck solid and difficult to remove. I had to burn out the remnants with a blow torch. As it came. I'll post some more photos later in the week. Cheers Tony