This operation manual covers the Yanmar 6LYA-STP / 6LY2A-STP marine diesel engines, designed for reliable marine propulsion. These engines represent a commitment to robust engineering and dependable performance, suitable for a wide range of marine applications. Their construction emphasizes durability and efficiency, ensuring optimal operation in demanding marine environments. This comprehensive manual provides essential information for the safe and effective operation, maintenance, and inspection of your Yanmar engine. It details system diagrams, troubleshooting procedures, and general operating instructions, empowering owners and technicians to maintain peak performance and longevity. Adhering to the guidelines within this document is crucial for ensuring the continued reliability and safety of your marine diesel engine.