This service repair workshop manual covers Mercury Mariner outboard engines from the 1987 to 1993 model years, specifically the 70, 75, 80, 90, 100, and 115 horsepower variants. These 2-stroke, water-cooled engines are known for their robust construction and reliable performance, suitable for a wide range of boating applications. Featuring CDI ignition, carbureted fuel systems, and available in remote or tiller steering configurations, these outboards offer a balance of power and efficiency. The manual details various configurations including manual or power trim/tilt systems and mechanical or power-assisted steering. The purpose of this manual is to provide comprehensive guidance for the maintenance, repair, and troubleshooting of your Mercury Mariner outboard engine. It includes detailed procedures for routine servicing, such as recommended oil types and replacement intervals for spark plugs, water pump impellers, and fuel filters. The manual also covers engine specifications, diagnostic information for common issues, and tuning procedures to ensure optimal performance and longevity. This resource is essential for owners, mechanics, and technicians seeking to maintain these engines to the highest standards.