The Volvo Penta AQ171 is a robust internal combustion marine engine, part of the established AQ Series. This inline 4-cylinder engine typically features a displacement of approximately 2.5 liters and produces between 130 to 150 horsepower, often utilizing fuel injection for efficient operation. Designed for sterndrive applications, it is commonly paired with SX or 200/270/280 drive units, offering either manual or automatic gearbox configurations. Its indirect cooling system, utilizing both raw water and freshwater, ensures reliable performance in demanding marine environments. This Workshop Service Repair Manual provides comprehensive guidance for the Volvo Penta AQ171 engine. It covers essential areas including engine mechanical and electrical systems, emission control, fuel system, and integrated clutch and transaxle components within the drive unit. Detailed illustrations, diagrams, and wiring schematics are included, alongside step-by-step instructions and a troubleshooting guide. This manual is an indispensable resource for owners, mechanics, and technicians seeking to maintain, diagnose, and repair their Volvo Penta AQ171 sterndrive system.