This Service Repair Workshop Manual covers Mercury Outboard Engines manufactured between 1965 and 1989. These engines, primarily 2-stroke outboards, were offered in 3-cylinder and 4-cylinder configurations, with power outputs ranging from 40 HP to 115 HP. The manual encompasses a wide variety of specific models, including those designated by HP and numerical prefixes, designed for diverse marine applications. Mercury engines are recognized for their robust engineering and reliable performance, making them a trusted choice for boaters. This comprehensive manual provides detailed guidance for servicing, restoring, maintaining, rebuilding, and diagnosing these Mercury Outboard Engines. It covers essential technical topics such as powerhead service, fuel and ignition systems, electrical systems, remote controls, power trim and tilt, and lower unit service, along with the hand rewind starter system. The manual includes clear, zoomable illustrations, exploded views, and part breakdowns to assist owners, mechanics, and technicians in performing maintenance and repairs effectively and efficiently.