Two-stroke engines are simple, light, and powerful. Unlike a four-stroke engine (the kind you find in a car), they can be operated at any angle. That's why you find them in lawnmowers, leaf blowers, chainsaws, and on boats as outboard motors. They come with significant disadvantages, however. They are terribly inefficient with fuel. They don't have a dedicated lubrication system and so burn the oil they use (if cars used two-stroke engines, they would burn a gallon of oil every 1,000 miles). And worst of all, they leak fuel through their exhaust by design.