This comprehensive service repair manual is specifically designed for Mercury Mariner 25, 25 Marathon, and 25 SeaPro outboard engines. It provides an in-depth guide to repairing and maintaining these engines, covering a wide range of topics including troubleshooting, disassembly, reassembly, and component replacement. The manual includes detailed diagrams, illustrations, and step-by-step instructions to ensure accurate and efficient repair procedures. With hundreds of pages of detailed information, it serves as an indispensable resource for technicians, mechanics, and owners seeking to understand and repair these outboard engines.

The Mercury Mariner 25, 25 Marathon, and 25 SeaPro outboard engines were compact and reliable power sources designed for a variety of small watercraft. These 2-stroke, single-cylinder engines produced 25 horsepower, making them suitable for inflatables, small fishing boats, dinghies, and tenders. Featuring a simple and robust design, these engines were known for their ease of maintenance and operation. The Mariner 25 offered a basic configuration, while the Marathon variant provided a slightly higher level of features and capabilities. The SeaPro version, geared towards commercial use, focused on durability and reliability, often employed in demanding applications like fishing and work boats. All models shared a common core design, utilizing a 25.2 cubic inch displacement engine with a manual starting system and a geared, cable-operated steering system.

These Mercury Mariner 25 engines were available in various configurations, including short and long shaft options, providing adaptability for different hull types and applications. They also featured different gear ratios, allowing users to optimize performance based on the boat's size and intended use. While the Mariner 25 series was discontinued, their legacy lives on in the used boat market, where they remain popular choices for their affordability and simplicity. Their 2-stroke design offers a balance of power and weight, making them an attractive choice for boaters seeking a lightweight and efficient motor. However, it's important to note that 2-stroke engines require a two-cycle oil mixture for lubrication, which adds an extra step to their maintenance routine. Regardless, these Mercury Mariner 25 engines continue to be a reliable option for boaters seeking a compact and economical power source for their smaller watercraft.