What is the main advantage of a two-stroke engine over a four-stroke engine?

The main advantage of a two-stroke engine over a four-stroke engine is that it produces power more often. In a two-stroke engine, the power cycle is completed in just two strokes of the piston (one complete crankshaft revolution), which means that it produces a power stroke with every revolution of the crankshaft. This results in a more immediate and frequent power output compared to a four-stroke engine, which requires four strokes (two complete crankshaft revolutions) to complete a power cycle and thus produces a power stroke every other revolution.

Because of this design, two-stroke engines can be smaller and lighter while still delivering high power output, making them particularly suitable for applications where weight and size are critical, such as in chainsaws, motorcycles, and small outboard motors. This characteristic also contributes to their simpler design and often lower manufacturing costs.

While two-stroke engines may have higher emissions or lower fuel efficiency, their ability to generate power more frequently is a key reason they are utilized in specific applications where power-to-weight ratio is more important than fuel efficiency or emissions.