This manual covers Mercury Mariner outboard motors, specifically the Mariner model from the 2-40 HP Series, manufactured between 1965 and 1989. These water-cooled, 2-stroke engines, equipped with carbureted fuel systems and oil injection, were designed for reliable performance. This comprehensive service and repair manual provides detailed information on engine specifications, including ignition and lubrication systems, as well as gearcase service, powerhead overhauls, and rewind starter repairs. The purpose of this English-language manual is to provide detailed, step-by-step instructions for both do-it-yourself enthusiasts and experienced mechanics. It includes hundreds of photos and illustrations, extensive troubleshooting guidance, and detailed wiring diagrams for electrical diagnostics. Safety information, including notes, cautions, and warnings, is integrated throughout. This manual is an essential resource for maintaining, troubleshooting, and repairing your Mercury Mariner outboard motor, ensuring optimal performance and longevity.