This manual covers the Mercury Mariner 75 HP Marathon outboard motor, manufactured between 1987 and 1993. As part of the Marathon Series, these naturally aspirated, carbureted 3-cylinder outboard engines are known for their robust engineering and reliable performance, delivering 75 horsepower. The inclusion of an oil injection system further enhances their operational efficiency and longevity, making them a trusted choice for various marine applications. This Factory Service Repair Manual provides comprehensive guidance for maintaining and repairing your Mercury Mariner 75 HP Marathon. It details essential service information, step-by-step repair instructions, and advanced testing techniques. The manual also includes a thorough troubleshooting guide to diagnose and resolve engine issues, along with practical maintenance tips to prevent future problems. With included wiring diagrams, this resource is designed to assist owners, mechanics, and technicians in keeping the engine in optimal condition.