Ok Before the appropriate point of ignition? I always see it happening when things have been going for a while then something like an air leak begins to take effect and things overheat??
In my Coleman and Tilley lamps I’ve only ever had this issue at light up, with insufficient pressure in the tank, or at close down when I’ve pricked the jet to make sure it’s clean for next time. In the second example I suppose it has temporarily upset the fuel/air pressure and there’s some kind of backfiring. I’m no engineer or mechanic so don’t trust my word on that explanation. I don’t think I’ve had underburn in any other of my many lamps. I’m sure there are many reasons for underburn in lamps other than pressure. In pressure stoves for example, cleaning the inner and outer burner caps often solves the problem, but having an outer cap that doesn’t sit flush on the burner is a usual cause; as is incorrect sized burner caps. I think there is an example discussed here on CPL where the Tilley injector tube was too long inside the mixing tube. If I recall correctly that also caused underburn in the mixing tube. Cheers Tony
Sort of - the first half of your sentence is correct. Underburn is caused when the pressure inside the tank, vapouriser and burner is insufficient to push the flamelets out of the burner holes or gauze...
