This service and repair workshop manual is for the Hino W04C-T marine engine. Designed for mechanics worldwide, it provides comprehensive instructions for servicing and repairing this specific engine model. The manual emphasizes the engineering quality and reliability of the Hino W04C-T marine engine, offering detailed guidance to ensure optimal performance and longevity for its intended marine applications. This manual serves as an essential resource for owners, independent service professionals, and technicians. It covers all major topics, including engine identification, general precautions, maintenance schedules and procedures, special tools, engine body, fuel system, cooling system, electrical system, and troubleshooting. With step-by-step instructions, diagrams, illustrations, wiring schematics, and specifications, this manual empowers users to perform maintenance, diagnostics, and repairs effectively and efficiently, mirroring the information used by authorized service departments.