This workshop service repair manual covers Yanmar marine diesel engines, including models 1GM10, 2GM20, 3GM30, 3HM35, and their 'F' and 'C' variants. These engines are engineered for reliable marine propulsion, offering robust performance and durability for a wide range of boating applications. Designed for both the do-it-yourself enthusiast and the experienced mechanic, these Yanmar engines are known for their quality and efficiency. This comprehensive English-language manual provides detailed guidance for maintaining and repairing your Yanmar marine diesel engine. It covers essential systems such as the fuel, lubrication, and cooling systems, along with the reduction and reversing gear and electrical components. With step-by-step instructions, detailed illustrations, and hundreds of photos, this manual is an indispensable resource for ensuring your engine operates at peak performance and longevity.