This manual covers the Mercury Mariner outboard engine, specifically the 8-9.9hp 4-stroke models. Renowned for their robust engineering and reliability, these engines are designed for dependable performance in various marine applications. Their efficient 4-stroke design ensures smooth operation and fuel economy, making them a practical choice for boaters seeking quality and durability. This comprehensive repair and service manual provides detailed, step-by-step instructions for maintenance and repair procedures. It includes hundreds of photos, illustrations, and drawings to aid in component identification and understanding. Essential information such as notes, cautions, and warnings are clearly marked to ensure safe and effective service. This guide is intended for both do-it-yourself enthusiasts and experienced mechanics, offering the necessary technical specifications and troubleshooting guidance to keep your Mercury Mariner engine operating at its best.