Yamaha F115LB Outboard Motor. 20-Inch Shaft 1.8-Liter In-Line 4 Remote Mechanical Control Electric Start Power Trim and Tilt Gray. The Yamaha F115LB is one of Yamaha's most popular midrange outboards, delivering an excellent balance of power, efficiency, and reliability. Powered by a 1.8-liter in-line 4-cylinder engine, it produces 115 horsepower in a lightweight, compact package. At just 377 pounds, the F115LB offers one of the best power-to-weight ratios in its class, making it an ideal choice