This manual covers the Mercury Mariner outboard engine, specifically the 3-cylinder models produced between 1987 and 1993, delivering 80 HP. Designed for reliable marine propulsion, these engines feature a robust 3-cylinder power head, carburetion fuel system, and adjustable timing for optimal performance. Key systems such as the oil injection, ignition, charging, and starting systems are integral to its operation, alongside an outboard gear housing and shock absorber for smooth handling. The inclusion of power trim with both side and aft fill reservoir designs, along with single ram functionality, further enhances its utility and user experience. This comprehensive Service Repair Workshop Manual provides detailed information for the maintenance and repair of your Mercury Mariner outboard. It includes general information, technical specifications, and step-by-step repair instructions accompanied by diagrams and illustrations. Essential sections on electrical and ignition systems, troubleshooting guidance, and engine installation procedures are also covered. This manual is an indispensable resource for owners, mechanics, and technicians seeking to ensure the longevity and optimal performance of their 80 HP Mercury Mariner outboard engine.