This manual covers the Yanmar 8SY Series marine engines, designed for reliable marine propulsion. These inboard diesel engines are engineered for demanding maritime applications, offering robust performance and durability. Understanding the operational guidelines and maintenance requirements is crucial for ensuring the longevity and optimal function of your Yanmar marine engine. The purpose of this English-language operation manual is to provide comprehensive information for owners and technicians. It details essential procedures, including pre-operation checks, engine operation, periodic maintenance schedules, and long-term storage instructions. This guide also includes warranty information for the USA market and technical specifications to assist in the proper care and upkeep of your Yanmar 8SY Series marine engine.