This digital workshop repair manual covers the Volvo Penta AQ131, AQ151, and AQ171 marine engines. These gasoline-powered engines, available in inline 4-cylinder (AQ131, AQ151) and inline 6-cylinder (AQ171) configurations, are designed for marine applications and utilize a closed cooling system with a heat exchanger. The AQ131 offers 130 hp, the AQ151 provides 150 hp, and the AQ171 delivers 170 hp, all paired with typical twin-carburetor and electronic ignition systems, and sterndrive transmissions. Their robust engineering ensures reliability for various maritime activities. This comprehensive English-language manual is designed for professional technicians and mechanics, providing detailed guidance for repair, maintenance, rebuild, refurbish, and restoration procedures. It includes high-quality photos, illustrations, and diagrams to facilitate understanding of complex tasks. The manual covers essential maintenance aspects such as recommended oil types and capacities, spark plug gap specifications, and replacement intervals for fuel filters and impellers. It is compatible with a wide range of Windows and Mac operating systems, ensuring accessibility for users.