It can be easily started Difference between two stroke and four stroke engine : Two stroke engine: 1. One working stroke in each cylinder per revolution in crankshaft. 2. Light in weight. 3. Moving parts are few. 4. Mechanical efficiency is more. 5. Thermal efficiency is less because a part of air fuel mixture gas as waste with the exhaust gas. Four stroke engine : 1. One working stroke in each cylinder per two revolution of crankshaft. 2. Size and weight of the engine is heavy and larger. 3. Moving parts are more in number. 4. Mechanical efficiency is less. 5. Thermal efficiency is more.