There are three holes in the 2 stroke 40hp outboard motor short shaft cylinder block, namely the intake hole, the exhaust hole and the ventilation hole, which are respectively closed by the piston at a certain time. Its work cycle consists of two itineraries:
1. First stroke: The piston moves upward from the bottom dead center. After the three air holes are simultaneously closed, the mixture entering the cylinder is compressed; when the air inlet is exposed, the combustible mixed air flows into the crankcase.
2. Second stroke of China outboard motor parts: When the piston is compressed to near the top dead center, the spark plug ignites the combustible mixture, and the gas expansion pushes the piston down to work. At this time, the air inlet hole is closed, and the combustible mixture sealed in the crankcase is compressed; when the piston approaches the bottom dead center, the exhaust hole is opened, the exhaust gas is flushed out; then the air exchange hole is opened, and the pre-compressed combustible mixture is flushed into The cylinder removes the exhaust gas and performs the ventilation process.