This manual covers marine engines, specifically models AQ105, AQ115, AQ130, AQ165, and AQ170. These naturally aspirated, 4-cylinder engines, available with displacements ranging from approximately 1.6 L to 2.6 L, are designed for sterndrive applications and feature either raw water or freshwater cooling systems. Built with renowned engineering quality, these engines are known for their reliability and performance in marine environments, making them a solid choice for various boating needs. The purpose of this comprehensive English-language workshop manual is to provide detailed service and repair information for the aforementioned models. It offers A-Z step-by-step instructions for all aspects of routine maintenance and repair, accompanied by clear pictorial guides and wiring diagrams to ensure ease of understanding. This manual is an essential resource for owners, mechanics, and technicians seeking to maintain, diagnose, and repair these marine engines effectively.