This manual pertains to the YANMAR YSM Operation Manual, a Marine Diesel Engine designed for marine propulsion. YANMAR is recognized for its commitment to engineering quality and reliability, ensuring robust performance in demanding marine environments. This operation manual provides comprehensive guidance for the effective and safe utilization of your YANMAR marine diesel engine. The purpose of this English-language operation manual is to serve as a definitive resource for owners and technicians. It covers essential information including engine specifications, installation procedures, post-launch operations, and detailed guidance on fuel and lubrication. Furthermore, it offers instructions for first-time engine startup, operational methods, regular inspection and maintenance schedules, and troubleshooting for simple malfunctions. The manual also includes electrical wiring diagrams, ensuring all aspects of the engine's operation and upkeep are thoroughly addressed.