This operation manual covers the YANMAR 2S(G) Series marine diesel engine. Engineered for reliable performance in marine applications, these 2-cylinder diesel engines are designed to meet the demanding requirements of maritime operations. Their robust construction and YANMAR's commitment to quality ensure dependable functionality for a wide range of marine vessels. This manual provides comprehensive guidance for the operation and maintenance of your YANMAR 2S(G) Series engine. It details essential procedures, including prior to operation checks, during operation guidelines, and stopping procedures. Furthermore, it covers routine maintenance, periodical checks, and specific disassembly and assembly instructions for key components such as the cylinder head, piston connecting rod, fuel injection systems, and reversing gear. This resource is designed to assist owners and technicians in maintaining the optimal performance and longevity of the engine.