During the power stroke of a two-stroke engine, what happens?

During the power stroke of a two-stroke engine, the key event is that the compressed fuel-air mixture ignites. This process occurs after the mixture has been compressed in the cylinder during the preceding stroke. As the piston reaches the top of its travel, the spark plug ignites the fuel-air mixture, resulting in an explosion that forces the piston back down. This motion is what generates the power needed to drive the engine and ultimately propel the boat.

Understanding this mechanism is essential, as it illustrates how two-stroke engines operate efficiently by completing a power cycle in just two strokes (one revolution of the crankshaft). The ignition of the compressed mixture is crucial for producing the energy that powers the engine during this phase.