Honda has developed 225 and 200-horsepower outboard motors powered by a 3.5-liter V-type 6-cylinder (V6) engine, the largest such outboard motors in the world, as the flagship models in its 4-stroke outboard motor series. The BF225/200 models are the first 4-stroke outboard motors to use the VTEC (variable valve timing and lift electronic control system), a variable intake and O2 feedback system. The resulting engine performance also makes them the world’s first outboard motors in the 200-hp class to achieve emissions levels that satisfy the year 2008 values for marine engine exhaust emissions set by the California Air Resources Board (CARB). At the same time, they have achieved a highly balanced performance improvement, with a maximum torque that is 10% greater and fuel consumption that is approximately 15% lower than previous models. The adoption of non-chrome coating methods for exterior parts on these motors has achieved the environmental compliance while maintaining coating quality on a par with previous models. In terms of comfort, their low vibration and low noise place them at the top of their class. The out bank exhaust manifold design with the same construction as V6 automotive engines and the use of a plastic inlet manifold makes these models lightweight and compact enough to replace conventional 2-stroke outboard motors without requiring any modification to the boat. Honda has achieved these performance levels while maintaining high reliability and simultaneously reducing cost by standardization of basic specifications and communizing parts with it’s automotive V6 engines.
Article of Honda R&D Technical Review Vol.14 No.1 (11 - 20)