This manual covers the Yanmar 1GM10(C), 2GM20(F)(C), 3GM30(F)(C), and 3HM35(F)(C) marine diesel engines. These engines are engineered for reliable marine propulsion, offering robust performance and durability for various maritime applications. Their design prioritizes efficiency and longevity, making them a trusted choice for boat owners and operators seeking dependable power on the water. This comprehensive workshop service repair manual provides detailed guidance for the maintenance and repair of your Yanmar marine diesel engine. It includes step-by-step instructions, detailed illustrations, exploded diagrams, and photographs to assist users of all skill levels, from novice to experienced technicians. The manual covers all areas of repair from A to Z, ensuring you can effectively maintain your engine, enhance its durability, and reduce reliance on external mechanics for routine tasks.