This comprehensive service repair manual provides in-depth guidance for servicing and repairing Mercury Mariner Outboard models 20 JET, 20, 25, 25 MARATHON, and 25 SEAPRO. This manual covers models manufactured in the United States with serial numbers 0G044027 and above, and in Belgium with serial numbers 09807909 and above. The manual includes detailed information on a wide range of topics, ensuring you have the knowledge and instructions needed for successful repairs. It features: * **Specifications:** Find the essential measurements and technical data for your Mercury Mariner Outboard. * **Maintenance:** Learn the recommended maintenance schedules and procedures to keep your engine running smoothly. * **General Information:** Understand the basics of your engine, including its components and functions. * **Outboard Installation:** Get step-by-step guidance on installing your outboard motor. * **Electrical System:** Dive into the intricacies of your outboard's electrical system, covering everything from ignition to charging. * **Fuel System:** Learn about the fuel system, including the carburetor, fuel pump, and emissions system. * **Powerhead:** Understand the intricacies of the powerhead, the heart of your engine. * **Mid-Section:** Learn about the mid-section, which connects the powerhead to the lower unit. * **Lower Unit:** Explore the lower unit, responsible for driving the propeller. * **Gear Housing:** Gain insight into the gear housing, a crucial part of the lower unit. * **Jet Drive:** For jet-powered models, this section covers the jet drive system in detail. * **Attachments and Control Linkage:** Learn about various attachments and how to adjust the control linkage. * **Throttle and Shift Linkage:** Understand how the throttle and shift linkages work. * **Tiller Handle:** Get familiar with the tiller handle and its operation. * **Side Shift:** For models with side shift, this section provides detailed information. * **Manual Starter:** Learn how to operate and maintain your outboard's manual starter. This manual is easy to follow, providing clear instructions and detailed diagrams to guide you through every repair process. Whether you're a seasoned mechanic or a DIY enthusiast, this manual is an invaluable resource for keeping your Mercury Mariner Outboard running at peak performance.

The Mercury Mariner 20 JET / 20 / 25 / 25 MARATHON / 25 SEAPRO outboard motors represent a range of reliable and popular power options for smaller recreational boats. These outboards, produced by Mercury Marine, are known for their robust construction, user-friendly features, and relatively simple design, making them suitable for a diverse range of boating activities. The model names indicate their horsepower ratings, with the 20 JET being a jet-driven model, while the others are traditional propeller-driven outboards. The "MARATHON" and "SEAPRO" designations likely reflect specific sub-models with features tailored to particular applications or markets. The Mercury Mariner 20 JET / 20 / 25 / 25 MARATHON / 25 SEAPRO outboards are powered by single-cylinder, four-stroke engines, offering a balance of power and fuel efficiency. These engines are often paired with smaller boats like dinghies, inflatables, and fishing boats, making them ideal for various water sports, fishing, and leisurely cruising. The "JET" model is specifically designed for shallow water operation, offering a powerful and efficient means of propulsion in areas where a traditional propeller might encounter obstacles like rocks or sandbars. The service manual for these models provides detailed instructions on performing maintenance and repairs, ranging from basic tasks like oil changes and spark plug replacement to more complex procedures involving the fuel system, ignition, and electrical system.