Honda has developed an all-new mid-sized outboard motor in the 4-stroke outboard motor series, the new BF90. Development of the new BF90 stressed enhancements to operating performance and fuel economy.The new 2006 BF90 uses a SOHC 2-stage VTEC and a dual independent circuit control cooling system. With refinements to the intake system general specifications, including the intake manifold and air silencer, this outboard motor achieves a 13% higher specific power (kW/L) than the current BF90. Fully considering the ways in which outboard motors are used, an open-loop lean burn control system, which uses oxygen sensors, was adopted, raising fuel economy by 20% over the current BF90. At the same time, the motor complies with 2008 CARB emission regulations and the 2006 European Recreational Craft Directive’s regulations.Modifications to the gear case shape have reduced water resistance. This, combined with a reduction in total motor weight, has enhanced operating performance. When used with an aluminum fishing boat, this new BF90 motor achieves 0-200 m acceleration 0.9 seconds faster than in the current motor, and a maximum speed that is 4.6 km/h higher.
Article of Honda R&D Technical Review Vol.19 No.1 (21 - 26)