The YANMAR SY Series Diesel Marine Engine represents a pinnacle of marine propulsion technology, engineered for reliability and robust performance in demanding maritime environments. Designed for a wide range of marine applications, these diesel engines are built with precision and durability in mind, ensuring consistent power delivery and operational efficiency. This series encompasses models such as the YANMAR 6SY-STP2, YANMAR 6SY655, and YANMAR 8SY-STP, each embodying YANMAR's commitment to quality engineering and advanced diesel technology. This comprehensive Service Repair Manual provides essential information for the maintenance and repair of the YANMAR SY Series Diesel Marine Engines. It is intended for service and repair professionals and covers critical areas including safety precautions, general service information, periodic maintenance schedules, and detailed procedures for engine components such as the fuel system, cooling system, lubrication system, turbocharger, starter motor, alternator, and the engine management system. The manual also includes a troubleshooting guide to assist in diagnosing and resolving common issues, ensuring optimal performance and longevity of your marine engine.