The Mercury Mariner 30/40 HP EFI 4-stroke outboard motor, produced between 2002 and 2005, represents a robust and reliable option for various marine applications. This early 2000s 4-stroke EFI generation is engineered for efficiency and performance, offering either 30 or 40 horsepower from its 3-cylinder, 735 cc (44.8 cu. in.) engine. Featuring Electronic Fuel Injection (EFI) and a water-cooled system, these outboards are designed for dependable operation and smooth power delivery, complemented by a 2.17:1 gear ratio and power trim and tilt functionality. This comprehensive Service Repair Manual provides essential information for maintaining and repairing your Mercury Mariner 30/40 HP EFI 4-stroke outboard. It covers critical areas including detailed maintenance procedures, troubleshooting guidance, in-depth technical specifications, and vital safety precautions. By following the instructions within this manual, owners, mechanics, and technicians can ensure optimal performance, longevity, and safe operation of their Mercury Mariner outboard.