This factory service repair manual provides comprehensive information for Mercury Mariner outboard engines. These engines, typically featuring a 323cc, 2-cylinder, 4-stroke configuration, deliver 9.9 HP or 15 HP and utilize a water-cooled system with carbureted fuel induction. The manual covers multiple model years, focusing on the intricate details of this engine's design and performance, ensuring its reliability and optimal function for various marine applications. This detailed manual is designed to assist owners, mechanics, and technicians in maintaining and repairing their Mercury Mariner outboard engines. It encompasses essential maintenance procedures, including lubrication with recommended Mercury 4-Stroke Outboard Oil and specific oil capacity details, as well as service schedules with intervals for initial and ongoing upkeep. Technical specifications, troubleshooting guidance for common issues, and information on the CDI ignition system, outboard lower unit transmission with forward, neutral, and reverse gears, and propeller selection are thoroughly explained.