ernie wrote an answer about Optimus Svea Stove on October 23, 2011
Unleaded like the name states, has no lead, but it does contain other additives. In a pinch, unleaded was used by me, and it worked. A little smokey on start-up, but ran well when warmed up fully. Not a wise choice because of the additives. Unleaded produces poisonous combustion by products and cause nasty deposits to build up inside the vaporizer/valve assembly. It may also effect your seals. As soon as suitable fuel was available,(naphtha from a hardware store), I swapped out the gasoline immediately. If I had a choice, I would NOT use unleaded.