This manual covers the Mercury 115 Four Stroke EFI, a robust marine engine designed for reliable performance. Engineered with advanced Electronic Fuel Injection (EFI) technology, this four-stroke outboard delivers efficient power and smooth operation. Its construction emphasizes durability and longevity, making it a dependable choice for a wide range of boating applications. The 115 HP rating ensures ample power for various watercraft, providing a responsive and capable experience on the water. This comprehensive Service Repair Manual provides detailed information for the maintenance, repair, and troubleshooting of your Mercury 115 Four Stroke EFI. It includes essential procedures such as scheduled maintenance, engine oil and gearcase lubrication, cooling system flushing, and corrosion control. The manual also covers spark plug maintenance, fuel system servicing, and diagnostic information, including troubleshooting guides for systems with and without computer diagnostics. Electrical system components like the alternator and starter motor, as well as the hydraulic steering system, are thoroughly detailed. Additionally, specific information for the 115 EFI Four Stroke, including propeller details and cooling system theory, is provided to assist owners, mechanics, and technicians in keeping the engine in optimal condition.