This manual covers the Mercury Mercruiser Alpha One Gen II sterndrive, a robust and reliable marine propulsion system designed for a wide range of boating applications. The Generation II model incorporates advancements in engineering to ensure optimal performance and durability on the water. This document details various aspects of the sterndrive, including standard and counter-rotation configurations and a comprehensive list of available gear ratios. It is intended for owners and technicians working with units from transom assembly serial number OD492742 and above. The purpose of this Service Manual is to provide comprehensive guidance for the maintenance, troubleshooting, and repair of the Mercury Mercruiser Alpha One Gen II sterndrive. It includes detailed procedures for general maintenance, specific component servicing, and complete disassembly and reassembly of the sterndrive unit and transom assembly. Technical specifications, including various gear ratios and serial number coverage for different configurations, are provided to ensure accurate identification and service. Safety guidelines and information on corrosion protection are also included to help maintain the longevity and performance of your marine drive system.