This comprehensive workshop service and repair manual covers the YANMAR 1GM10 and 2GM20 marine diesel engines. These engines are engineered for reliable marine propulsion, offering robust performance and durability for a wide range of maritime applications. The YANMAR 1GM10 and 2GM20 models are recognized for their quality construction and dependable operation, making them a preferred choice for boat owners and operators seeking efficient and trustworthy power solutions. This manual provides detailed guidance for all servicing, repairs, and routine maintenance procedures. It includes step-by-step instructions accompanied by clear diagrams, such as wiring schematics, to facilitate understanding and execution of tasks. The scope of this document ensures that owners, technicians, and mechanics have the necessary information to effectively maintain and repair their YANMAR marine diesel engines, promoting longevity and optimal performance.