This manual covers the Continental A-Series aircraft engines, including models A50, A65, A75, and A80. These horizontally opposed, four-cylinder, air-cooled piston engines were produced prior to the 1970s and are known for their reliability and robust engineering, powering a wide range of aircraft such as Cessna and Piper models. With horsepower ranging from 50 to 80 HP and displacements around 200-300 cubic inches, these engines feature overhead valve actuation with hydraulic lifters and typically utilize magneto ignition and a downdraft carburetor or fuel injection. Their direct drive configuration means no integrated transmission is present. This comprehensive English-language manual provides essential information for the upkeep and repair of your Continental A-Series engine. It encompasses detailed overhaul procedures, parts listings, service guidelines, operator’s information, fuel injection specifics, and troubleshooting assistance. The manual is designed to be fully bookmarked and searchable, offering clear instructions and technical specifications to help owners, mechanics, and technicians effectively maintain engine performance, ensure safety, and address potential issues. It includes guidance on lubrication, such as recommended oil types and capacities, and general engine care tips.