This Service Repair Manual covers the Mercury Mariner outboard motor, a robust and reliable power unit designed for a variety of marine applications. Engineered for performance and durability, the Mariner series is known for its efficient fuel injection system and powerful 4-cylinder, 3.0L engine, delivering 125 horsepower. Its water-cooled design and electronic ignition ensure consistent operation, while the outboard lower unit with forward, neutral, and reverse gears provides versatile control. This manual is intended to provide comprehensive information for owners and technicians alike. The scope of this manual encompasses all essential aspects of maintaining and repairing the Mercury Mariner outboard motor. It details critical maintenance procedures, including recommended fuel types, gearcase lubrication, and trim/tilt fluid specifications. Technical specifications, troubleshooting guides, and diagnostic information are provided to assist in identifying and resolving issues. By following the instructions and guidelines within this English-language service manual, users can ensure the longevity, optimal performance, and safe operation of their Mercury Mariner outboard motor.