Gas engines are internal combustion engines that use gasoline as their fuel source. They are typically used in cars, trucks, boats, and other vehicles, as well as in lawn mowers, generators, and other small engines. Gas engines work by burning a mixture of gasoline and air in a cylinder, which creates a spark that ignites the fuel and causes the piston to move. The movement of the piston creates power, which is then used to turn the crankshaft and drive the vehicle.