This workshop service manual covers the Mercury Mariner 4 HP 4-stroke outboard motor. Engineered for reliability and performance, this gasoline-powered motor features a 1-cylinder, water-cooled engine delivering 4 HP. Its robust design and efficient operation make it suitable for a variety of marine applications. The transmission system includes Forward, Neutral, and Reverse gears, offering versatile control. Standard or long shaft variants are available, catering to different boat configurations. This comprehensive English-language manual provides detailed guidance for maintaining and repairing your Mercury Mariner outboard. It includes essential information on lubrication, fuel system requirements, ignition system specifications, and seasonal procedures such as winterization. Owners, mechanics, and technicians will find step-by-step instructions for routine maintenance and troubleshooting, ensuring optimal performance and longevity of the engine. Key specifications, including oil type and capacity, spark plug details, and safety features like the kill switch lanyard, are thoroughly explained within its 260 pages.