This Service Repair Workshop Manual covers Mercury Outboard motors manufactured between 1966 and 1989. These engines, ranging from 90hp to 300hp, feature an electrical ignition system and a rewind starter. The manual provides comprehensive information for maintaining and repairing these reliable marine propulsion units, designed for a wide array of boating applications. The purpose of this manual is to serve as an exhaustive guide for owners, mechanics, and technicians. It details procedures for setup, installation, repair, tuning, troubleshooting, and maintenance, covering all aspects from A-Z. Included are detailed pictures, diagrams, parts numbers, and information on electrical ignition systems, fuel systems, and the lower unit, ensuring thorough understanding and effective servicing of your Mercury Outboard.