This manual covers the YANMAR 4BY-150 Series Marine Inboard Engines. These diesel engines are engineered for reliable marine propulsion, offering robust performance across various applications. The series includes Inline 4-Cylinder and Inline 6-Cylinder configurations, with models such as the 4BY150, 4BY180, 6BY220, and 6BY260, designed to meet demanding operational requirements.

This comprehensive service repair manual provides essential information for maintaining and repairing your YANMAR marine engine. It details critical procedures, technical specifications, and recommended maintenance schedules, including guidance on oil type and capacity. By following the instructions within this manual, owners and technicians can ensure optimal performance, longevity, and safe operation of the engine.