What most people do not understand is that the stoichiometric range for gasoline is very narrow - 13-17% typically. Liquid gasoline will not light as you said. The key is getting the spark through the vapor in the stoichiometric range fast enough that it does not ignite. The problem with gasoline is that it has a lot of vapor that causes big flashes when it ignites.
Most people do not think about it but the electric motor in their car's tank is cooled by the gasoline. Putting an electric motor in a diesel tank is trickier as it has so much less vapor that it is much easier to get a set of conditions where it is stoichiometric around the pump - gas tanks are usually full of vapor, i.e. no oxygen.