This workshop service repair manual covers the Mercury Mariner 115 HP 4 Cylinder outboard engine models manufactured between 1988 and 1993. Designed for reliability and performance, these engines are engineered with a 4-cylinder configuration, delivering 115 horsepower. Key features include a carbureted fuel system, oil injection, and a comprehensive electrical system encompassing battery, charging, and starting components. The manual details ignition systems, timing adjustments, and wiring diagrams, providing in-depth information for optimal engine operation and longevity. This comprehensive English-language manual serves as an essential resource for owners, technicians, and mechanics. It provides detailed guidance on all aspects of maintenance, repair, and troubleshooting, including general information, electrical systems, fuel and ignition systems, powerhead and lower unit procedures, and specialized sections covering power trim and tiller handle operations. With full printable access and coverage for all models and trims, this manual ensures that users have the necessary information to perform diagnostics, routine maintenance, and complex repairs effectively.