This workshop service repair manual covers Mercury Outboard models produced between 1966 and 1989, encompassing all generations. These versatile outboard engines, ranging from 90HP to 300HP, are known for their robust engineering and reliable performance across various watercraft applications. The manual provides comprehensive details on the diverse engine configurations, including inline and V-type setups, and their water-cooled systems, ensuring owners can maintain their Mercury Outboard for optimal operation. The purpose of this manual is to provide detailed guidance for every repair procedure, adjustment, and overhaul. It includes exploded views, diagrams, illustrations, and step-by-step instructions to assist with do-it-yourself servicing. Whether performing routine maintenance, addressing troubleshooting issues, or undertaking more complex repairs, this English-language resource offers the necessary technical specifications and procedures. This manual is an essential tool for owners and technicians alike to ensure the longevity and peak performance of their Mercury Outboard engines.