This workshop service repair manual covers the Yanmar 6LYA-UTE and 6LYA-STE marine diesel engines. These inline 6-cylinder engines feature a displacement of 5.81 liters, direct injection, and are turbocharged and intercooled, delivering robust performance with the 6LYA-UTE producing up to 370 HP and the 6LYA-STE up to 350 HP. Engineered for reliability and efficiency, these engines are designed to meet the demanding requirements of marine applications. This comprehensive manual provides detailed information essential for the maintenance, repair, and troubleshooting of your Yanmar engines. It includes step-by-step instructions for disassembly and reassembly, extensive electrical system diagnostics, and an advanced troubleshooting guide. With hundreds of photos, illustrations, and detailed wiring diagrams, this manual serves as an indispensable resource for owners, mechanics, and technicians to ensure optimal engine performance and longevity.