The YANMAR 6EY18 Series represents a robust line of marine diesel engines designed for auxiliary applications. These engines are engineered for reliability and efficient operation in demanding marine environments. The 6EY18 models, including the 6EY18LW and 6EY18ALW, feature a 6-cylinder vertical, 4-cycle configuration with a substantial 42.75L displacement and water-cooled operation, underscoring their capacity for sustained performance. This comprehensive service repair manual provides detailed guidance for the YANMAR 6EY18 Series marine diesel engines. It covers essential aspects such as general information, technical specifications, maintenance procedures, tightening torques, and the use of special tools. The manual also includes in-depth information on engine structure, installation, air charging, exhaust, lubrication, cooling, fuel oil, speed control, starting, and control air systems. With step-by-step instructions, detailed illustrations, and coverage of safety and control systems, this manual is an indispensable resource for owners, mechanics, and technicians to ensure optimal performance and longevity of their YANMAR engines.