Honda BF250 Engine - Environmental Performance  The new Honda
Marine BF250 outboard engine boasts the best fuel economy level
in its class. Discuss how second generation lean burn control
contributes to increased fuel efficiency.  Lean Burn Control
(incorporated in Honda marine engine models BF40, BF50, BF60,
BF75, BF90, BF135, BF150, BF200, BF225, and BF250) automatically
adjusts the air/fuel mix according to speed and load while
maximizing power throughout the acceleration range - providing
as much as 20 percent greater fuel economy in cruise mode (2,000
to 4,500 rpm). Concerning the new BF250 engine, this feature has
been enhanced to improve fuel efficiency even further in
specific cruising ranges, resulting in best-in-class fuel
economy - 16 -30 percent better than competitive models,
depending on specific running conditions. As the below diagram
depicts, the lean burn control system accurately measures and
monitors the fuel delivered to the engine's combustion chamber
(under various loads and throughout