This manual covers the Yanmar 6LY2-STE, 6LY2A-STP, and 6LYA-STP marine diesel engines. These inline 6-cylinder engines are turbocharged and intercooled, designed for robust performance in marine applications. With displacements of 11.042 liters, they offer power outputs ranging from 244 kW (327 HP) to 313 kW (420 HP), suitable for various vessel types. The engines feature direct injection, common rail fuel systems, and liquid cooling, ensuring efficiency and reliability for demanding maritime operations. This comprehensive service repair manual provides detailed information essential for maintaining and repairing your Yanmar marine diesel engine. It includes procedures for inspection, servicing of engine parts, fuel injection equipment, turbocharger, lubrication, cooling systems, and reduction gears. Additionally, the manual covers electrical systems, troubleshooting, and disassembly/reassembly instructions. With photo illustrations, schemes, and diagrams, this English-language guide is designed to assist owners, mechanics, and technicians in ensuring optimal engine performance and longevity.