This manual covers the YANMAR 3YM20, 3YM20C, 3YM30, 3YM30C, 2YM15, and 2YM15C marine diesel engines manufactured in 2005. These engines are engineered for reliability and performance in marine applications, featuring robust construction and efficient operation. The YANMAR series offers dependable power, with configurations including 2-cylinder and 3-cylinder options, designed to meet the demanding requirements of various marine vessels. Their advanced engineering ensures consistent performance and longevity, making them a trusted choice for boat owners and operators.

The purpose of this comprehensive Service Manual / Workshop Manual is to provide detailed guidance for the maintenance, repair, and troubleshooting of these YANMAR marine engines. It includes essential information on scheduled maintenance, engine specifications, electrical system diagnostics, and repair procedures, including full engine rebuilds. Furthermore, the manual contains vital diagrams and charts for cooling systems, raw water flow, and components such as raw water pumps and heat exchangers. This resource is indispensable for owners, technicians, and mechanics seeking to ensure optimal performance and longevity of their YANMAR engines.