Engineers designed Yamaha's 90 horsepower outbaords to work with average-sized motor boats.
Yamaha Motor Corporation featured more than 10 makes and 50 different outboard models in 2010, all with varying levels of power. Yamaha has two offerings if you are looking for a model with about 90 horsepower: the F90 Midrange and the F115 Jet. Both featured a four-stroke, four-cylinder engine with different performances but similar operational systems.
Midrange
Meant to be particularly quiet and energy efficient, Yamaha's Midrange comes in seven models with the F90 as the largest --- with a maximum of 90 hp. This motor's four-cylinder engine displacement is 1,596 cc (97 cubic inches) and the compression ratio is 9.6 to 1. The F90 Midrange also features an alternator output of 25A at wide open throttle, a range of 5,000 to 6,000 rpm, and a weight of 369 lb. It can fit 20 or 25-inch shaft lengths.
Jet Drive
Yamaha's Jet Drive make of outboard motors enables boats to traverse even choppy waters and rapids. The F115 Jet model features a four-stroke, four-cylinder that operates just under 90 horsepower at 5,500 rpm. The motor also has a displacement of 1,741 cc (106.2 cubic inches) and a compression ratio of 9.0 to 1. It has a wide open throttle alternator output of 25A, an rpm range of 5,000 to 6,000 and a shaft length of 25 inches. It weighs 415 lb.
Systems
Though specific performance specifications vary, both the F90 Jet and the F90 Midrange feature the same engineering systems. This includes a double-overhead camshaft fuel injection system, a wet-sump lubricator, and a micro computer ignition. Both also feature an electric starter and have a California Air Resources Board (CARB) emissions rating of three stars.
Tags: alternator output, compression ratio, cubic inches, cubic inches compression, displacement cubic