This Service Repair Manual covers the Mercury Mariner outboard motor, specifically the First Generation models produced between 1988 and 1993. These engines are known for their reliable 4-cylinder, 115 HP powerplants, featuring a water-cooled system, carbureted fuel delivery, and CDI ignition. Designed for dependable performance on the water, the Mariner series offers robust engineering and a straightforward operational design, making it a popular choice for various boating applications. This comprehensive manual provides essential information for maintaining and repairing your Mercury Mariner outboard. It details routine maintenance procedures, including recommended intervals for water pump impeller replacement and specific gearcase oil types. Technical specifications, troubleshooting guidance, and information on the electric start and outboard lower unit drive system are also included. This resource is invaluable for owners, mechanics, and technicians seeking to ensure the longevity and optimal performance of their Mercury Mariner engine.