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2001 Engine Preview Page 7

Engine Overview
Engines — By the PMY staff

Outboards —
Yamaha Marine
2001 Engine Preview


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•  Yamaha Marine  

The big news in outboards today? Yamaha’s finally done it. For almost five years the engineers of this forward-thinking company have been quietly working on a project that more than a few stateside critics said was doomed to fail: development of a workable, lightweight, reasonably sized, high-horsepower four-stroke outboard. Last September, with characteristic modesty despite the stunning nature of the achievement, the company unveiled its new F225, a 225-hp V-6 that according to Yamaha exceeds federal EPA emission requirements for 2006 and weighs only about 80 pounds more than a conventional two-stroke Yamaha 225-hp.

While it’s acknowledged that four-stroke technology is much cleaner, quieter, smoother, and more fuel-efficient in operation than the old-fashioned two-stroke technology that’s been around since the turn of the last century, no manufacturer has pushed the concept as hard as Yamaha. In creating the F225 the company started from scratch, deciding early on that adapting an automotive engine, as Honda did, would produce too large a package.

Instead, the engineers created an electronically fuel-injected, 60-degree V-6 DOHC power unit that saves space by reversing intake and exhaust system layouts, positioning precision-tuned intake tracks on the outside of the power unit, and ensconcing the exhaust tracks compactly inside, between the cylinder banks. The configuration, which is patented, also houses both throttle bodies and fuel injectors inside each intake track. All this not only saves space, but it also keeps electrical wiring associated with the injectors away from the cowling, thereby increasing reliability and longevity. Additionally, Yamaha’s engineers have designed a direct-drive alternator for the F225 that is mounted underneath the flywheel on top of the engine, a setup that’s more compact than a conventional belt-driven design.

Considerable field testing of the F225 took place in the United States last year prior to the engine’s introduction at Boating Week, a trade show produced by the National Marine Manufacturers Association. The event was highlighted by a Boating Innovation Award for Yamaha and its new, standard-setting outboard. Reports from builders who have tested the engine on their boats—folks like Grady-White, Scout, Pursuit, and Regulator—are generally enthusiastic, and everyone is reportedly antsy to receive the first production engines, which are not likely to become available until later this spring. However, Yamaha says the F225 will be available for magazine testing in late February or early March. Stay tuned.

Yamaha Marine (800) 889-2624. Fax: (770)-420-5833. www.yamaha-motor.com.

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This article originally appeared in the May 2003 issue of Power & Motoryacht magazine.

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