This service repair manual covers the Mercury Mariner 100HP 4 Cylinder Outboard Engine manufactured between 1988 and 1989. Designed for marine applications, this engine offers reliable performance and robust engineering, making it a dependable choice for various boating needs. Its four-cylinder configuration and 100 horsepower output are optimized for efficiency and power, reflecting the quality expected from Mercury Mariner outboards of this era. This comprehensive manual is intended for both do-it-yourself owners and experienced mechanics. It provides detailed information on maintenance procedures, troubleshooting common issues, and essential technical specifications for the 1988-1989 Mercury Mariner 100HP 4 Cylinder Outboard Engine. By following the guidelines and instructions within this English-language manual, users can effectively maintain their engine, ensure optimal performance, and address potential repairs with confidence.