This workshop service manual covers the Mercury Mariner 9.9 Bigfoot outboard motor. Designed for reliable performance, this 4-stroke, water-cooled engine features a 2-cylinder, 323 cc displacement, delivering 9.9 HP. Its carburetor fuel induction system and CD ignition ensure efficient operation. The outboard drive system is equipped with a gear ratio of 2.15:1 and offers Forward, Neutral, and Reverse gear selection. This manual provides comprehensive information for maintaining and operating this robust marine propulsion unit. The purpose of this manual is to provide detailed guidance for the maintenance, repair, and servicing of the Mercury Mariner 9.9 Bigfoot outboard motor. It includes essential technical specifications, lubrication requirements, recommended fuel and oil types, and spark plug gap specifications. Owners, technicians, and mechanics will find step-by-step procedures, diagnostic information, and troubleshooting tips to ensure optimal performance and longevity of the engine. This comprehensive resource aims to empower users with the knowledge necessary for effective vehicle upkeep.