Oh boy, this ought to be fun. Remember that "Usually" is a very strong term sometimes. A preheat cup and or an NRV style check valve "usually" means kerosene/paraffin. Although very early products from the United States used NRV's for gasoline/petrol powered products. The region and manufacturer helps sometimes too. Tilley, Vapalux/Bialaddin and Petromax products are "usually" kerosene/paraffin. However there were gasoline/petrol lanterns made by Petromax; they were recalled and changed to kerosene only if I remember correctly. Lanterns built outside the United States "usually" do not run on gasoline/petrol. There were however some Hasag lanterns that ran on gasoline/petrol. Most lanterns from the United States were gasoline/petrol models; but there were several models built for export only that ran off kerosene/paraffin. It's a familiarity thing, you'll get used to it.
OK i get it. I see some lamps with a (fuel tube?) that loops or doesn't go straight around the mantle area and i didn't know if that was a way of replacing the cup.
Those loops, cups etc., mean that the generator is for Coleman fuel and they are all variations of the Coleman Q-99 generator. If I recall correctly, Coleman were the first to have the quicklight idea, Jeff.
Generally (1st cousin of 'usually'), gasoline / Coleman fuel lamps and lanterns won't have a pressure release, will have a positive 'shut-off' valve and won't use rubber seals and gaskets. They're on top of the other features that have already been mentioned. As a general rule, if you've no idea which fuel to use and you can't get an answer here, I'd err on the side of caution and assume it was kerosene and try that first. If the lantern doesn't burn properly or at all, then it's probably gasoline/Coleman. Mind you, I've never been so stuck in 10 years that I've had to resort to that...
