This service manual covers the Mitsubishi K21 and K25 internal combustion engines, designed for demanding industrial applications including forklifts, generators, and agricultural equipment. These engines are engineered for reliability and efficiency, utilizing LPG as their fuel source and incorporating advanced emission control systems such as a PCV Gas Recirculation Device and electric-controlled specifications. The manual details the engine's operational mechanisms, including its lubrication and cooling systems, and specific components like the vaporizer, distributor, starter motor, and alternator. This comprehensive 214-page service manual provides essential information for maintaining and repairing the Mitsubishi K21 and K25 engines. It includes detailed procedures for troubleshooting, general engine tune-ups, engine mechanical and electrical adjustments, and tightening torque specifications. The manual also covers engine control, fuel system diagnostics, and repair limits, offering guidance on engine identification and the proper use of special service tools. This resource is intended for owners, mechanics, and technicians to ensure optimal performance and longevity of the engine.