This comprehensive service manual provides detailed instructions for maintaining and repairing Mercury Mariner Outboard 225 225EFI 250EFI 3.0-liter engines. It covers models including the 225/250 EFI and 3.0 Liter Marathon/3.0 Liter SeaPro, with serial numbers starting from US 0D280813 and above. Designed for both DIY enthusiasts and experienced mechanics, this manual offers step-by-step guidance, backed by hundreds of images and illustrations, to clearly walk you through every service and repair procedure. The manual is organized to cover all aspects of the engine, starting with essential information and covering electrical systems, fuel systems, the powerhead, mid-section, lower unit, and attachments/control linkage. You'll have access to detailed information and instructions to help you troubleshoot and resolve common issues, and perform necessary maintenance tasks effectively.

The Mercury Mariner 225 2-stroke outboard motor, a powerful and robust engine, is a legendary choice for boaters seeking high performance and reliable propulsion. This powerful engine, spanning the 225EFI and 250EFI models, boasts a 3.0-liter displacement, delivering impressive power and torque for a wide range of applications. Its renowned 2-stroke design ensures a lightweight and compact construction, ideal for maneuverability and agility on the water. Whether cruising leisurely or powering thrilling watersports, the Mariner 225 EFI/250 EFI thrives in diverse boating environments, offering a seamless blend of power and efficiency. The Mercury Mariner 225/250 EFI outboards are renowned for their advanced electronic fuel injection system, ensuring precise fuel delivery and optimal engine performance. Digital throttle and shift controls enhance user friendliness and responsiveness, while the integrated engine management system continuously monitors vital engine parameters, delivering exceptional reliability and durability. These outboard motors are engineered for effortless maintenance and boast a wide range of available parts, ensuring long-lasting performance and peace of mind. With its exceptional power, efficiency, and user-friendly features, the Mercury Mariner 225/250 EFI series remains a highly sought-after choice for boaters seeking a dependable and exhilarating boating experience.