This comprehensive operators manual provides detailed instructions and essential information for operating Lycoming Aircraft Engines, specifically the O-235 and O-290 models. The manual covers a wide range of topics, ensuring you have a thorough understanding of these powerful engines. It delves into crucial aspects like pre-flight inspection, startup procedures, engine operation, maintenance schedules, troubleshooting, and emergency procedures. You'll find clear and concise instructions, supported by diagrams and illustrations, making navigation and comprehension effortless. Whether you're a seasoned pilot or new to these engines, this manual serves as your indispensable guide, empowering you with the knowledge and confidence to safely operate and maintain your Lycoming O-235 and O-290 engines.

The Lycoming O-235 and O-290 series of horizontally opposed, four-cylinder, air-cooled aircraft engines were workhorses of the aviation industry, powering a diverse range of aircraft from small general aviation planes to military trainers and agricultural aircraft. These engines, introduced in the mid-20th century, were known for their reliability, simplicity, and ease of maintenance. The O-235, with a displacement of 235 cubic inches, produced a respectable 118 horsepower, while the O-290, with a larger 290 cubic inch displacement, pushed out 135 horsepower. Both engines were designed with a robust, cast aluminum crankcase, forged steel connecting rods, and a direct-drive, single-stage reduction gearbox. The engine's simplicity allowed for quick and straightforward servicing, contributing to its popularity among pilots and mechanics alike.

The O-235 and O-290 engines were highly versatile, propelling various aircraft types throughout their production run. They found their niche in the realm of general aviation, powering iconic aircraft such as the Cessna 150, 152, and 172, as well as Piper's popular Cherokee series. These engines also found service in military training aircraft, like the Beechcraft T-34 Mentor, and agricultural planes, tasked with crop dusting and spraying. Their reliability and durability ensured consistent performance in demanding environments, making them a dependable choice for both recreational and professional aviation applications.