This workshop service manual provides comprehensive information for the Mercury Mariner 9.9 Bigfoot outboard motor. This 4-stroke engine, with a displacement of 323 cc and a power output of 9.9 HP, is designed for reliable performance on the water. Its water-cooled system ensures efficient operation, and it features an outboard gearcase with forward, neutral, and reverse gears. The fuel system utilizes unleaded gasoline delivered via a carburetor, and the ignition system is a CDI type. This manual covers a robustly engineered product known for its dependability. The purpose of this English-language workshop service manual is to serve as an authoritative resource for maintaining and repairing the Mercury Mariner 9.9 Bigfoot. It details essential procedures, technical specifications, and troubleshooting guidance. Owners, mechanics, and technicians will find detailed information on engine specifications, fuel and ignition systems, cooling, electrical, and control systems. The manual aims to facilitate proper upkeep and efficient problem resolution, ensuring the longevity and optimal performance of the outboard motor.