This workshop service manual covers the Mercury Mariner 70 HP 3-Cylinder Outboard, produced between 1987 and 1993. Engineered for reliable performance on the water, this outboard features a robust 3-cylinder, water-cooled engine with CDI ignition and carburetor fuel delivery, delivering a consistent 70 horsepower. Its durable construction and proven design make it a dependable choice for a variety of boating applications, emphasizing efficiency and longevity. This comprehensive manual provides essential information for the maintenance, repair, and operation of your Mercury Mariner outboard. It details routine maintenance procedures, including recommended fluids and capacities, as well as technical specifications for engine and electrical systems. Troubleshooting guidance, diagnostic procedures, and component-level repair instructions are included to assist owners, technicians, and mechanics in ensuring the optimal performance and longevity of the vessel.