This manual covers the Mercury Mariner 70 HP 3 Cylinder Outboard, manufactured between 1987 and 1993. This engine is engineered for reliable performance, featuring a robust 3-cylinder configuration and a dependable carburetion fuel system. Its design prioritizes durability and efficiency, making it a suitable choice for various marine applications. The oil injection system and ignition system are integral components designed for optimal operation. This comprehensive Factory Service Repair Manual provides essential information for maintaining and repairing your Mercury Mariner outboard. It details step-by-step repair procedures, advanced troubleshooting guides, and included maintenance tips. Coverage extends to critical systems such as electrical service, wiring diagrams, battery and charging systems, starting systems, timing adjustments, synchronizing, lower unit and gear housing maintenance, power trim, and controls. This manual is an indispensable resource for owners and technicians alike.