This Service Repair Manual covers the YANMAR 6BY2 Marine Diesel Engine, designed for marine propulsion applications. This inline 6-cylinder diesel engine offers robust performance, with horsepower ratings ranging from 230 to 310 HP depending on the specific model variant. Its engineering is focused on reliability and efficiency, making it a dependable choice for various marine vessels. This manual provides comprehensive guidance for the maintenance, repair, and troubleshooting of the YANMAR 6BY2 engine. It includes detailed technical specifications, step-by-step procedures for service and repair, safety precautions, and essential information to ensure optimal performance and longevity. This resource is intended for owners, technicians, and mechanics seeking to maintain and service their YANMAR marine diesel engines effectively.