The YANMAR 4BY2 is a robust Marine Diesel Engine designed for reliable marine propulsion. Built with YANMAR's renowned engineering quality, this internal combustion engine is a testament to durability and performance in demanding marine environments. Its primary intended use is for marine propulsion, offering a powerful and efficient solution for a variety of watercraft. This Service Repair Manual provides comprehensive guidance for the YANMAR 4BY2 Marine Diesel Engine. It covers essential maintenance procedures, troubleshooting steps, and technical specifications necessary for optimal operation and longevity. The manual is an indispensable resource for owners, mechanics, and technicians, ensuring that the engine is maintained and repaired to the highest standards, facilitating safe and efficient operation on the water.