This workshop service manual covers the YANMAR 6EY18 Series marine auxiliary diesel engines, including models YANMAR 6EY18LW and YANMAR 6EY18ALW. These 4-cycle, water-cooled, 6-cylinder vertical engines are designed for reliable performance in demanding marine applications. With a substantial 42.75L displacement, these engines are engineered for robust operation and longevity. This comprehensive manual provides essential repair and service information designed to keep your YANMAR 6EY18 Series engine operating at peak performance. It includes detailed sections on general information, specifications, maintenance procedures with illustrations and diagrams, tightening torques, special tools, engine structure, installation, and various systems including fuel, lubricating oil, cooling water, exhaust, speed control, starting, and generator systems. The content is structured to assist both do-it-yourself owners and experienced mechanics in effectively servicing and maintaining the engine.