This service manual covers the Mitsubishi K Series internal combustion engines, specifically models K21 and K25. These gasoline engines are engineered for robust performance and reliability, making them suitable for a wide range of applications including industrial equipment, agricultural machinery, and other specialized devices. Their design emphasizes durability and efficient operation, ensuring consistent power delivery for demanding tasks. This comprehensive English-language service manual provides detailed information to assist in the maintenance and repair of your Mitsubishi K Series engine. It includes procedures for engine maintenance, tune-ups, and troubleshooting, along with technical specifications such as tightening torques and repair limits. Coverage extends to all major engine components, including the lubrication, cooling, fuel, and electrical systems, as well as emission control and engine control systems, ensuring that owners, mechanics, and technicians have the resources needed for optimal engine upkeep and performance.