Because Honda Marine’s BF90 affords boaters the fuel efficiency and quiet operation of Honda’s legendary technology combined with the lightweight and explosive acceleration traditionally associated with two-stroke outboards, they’ll plenty of them in action on the water this Easter.
The BF90’s 1.5-litre, in-line 4-cylinder engine boasts Honda’s exclusive Boosted Low Speed Torque (BLAST) system, Variable Valve Timing and Electronic Lift Control (VTEC™ – BF90), Lean Burn Control, and Three Way Cooling.
Ideal for pontoons, aluminum bass and walleye boats, small center consoles, skiffs, and inflatables, Honda’s BF90 EFI redefines four-stroke performance with the patented BLAST system.
Holeshot and acceleration are dramatically improved by advancing ignition spark timing to within one degree of the knock limit during “hammer down” acceleration. The Engine Control Module (ECM) then steps in to increase injector timing, creating a more potent air/fuel mixture. The resulting boost in available torque at low rpm contributes to a strong holeshot to get the boat up on plane quickly. The ignition spark timing is appropriately adjusted under slower throttle advancement, ensuring a leaner air/fuel mix and class-leading fuel efficiency.
Further contributing to the engines’ outstanding fuel efficiency is Honda’s exclusive Lean Burn Control, which pairs the ECU with an oxygen (O2) sensor to adjust the air/fuel mixture according to speed and load, maximizing efficiency in “cruise mode.”
Derived from racing and first appearing on the Acura NSX sports car, VTEC™ utilizes mild cam lobes to operate the intake valves at low rpm, and then engages a high-output lobe for high-rpm operation. The resulting boost in available power provides outstanding mid-range acceleration.
Further contributing to the BF90’s explosive performance is Honda’s all-new high-performance gear case. A longer anti-ventilation plate helps trap water flowing to the propeller to minimize porpoising, while a streamlined front and longer bullet reduce drag for enhanced acceleration and fuel efficiency. A front splash plate reduces spray from the hull bottom, maintaining a dry deck above, and a 2.33:1 gear ratio affords the use of 13- to 14-inch diameter propellers for heavier loads.
The engines’ best-in-class 44-amp alternator (35 amps of battery charging), ignition, and other critical electrical components are mounted near the top of the powerhead to ensure that all are kept cool and dry.
High Performance in a Durable Package
To ensure longterm durability, Honda engineers designed the first individually-controlled cylinder cooling system for outboard engines – Three Way Cooling. The system reduces engine heat by allowing the cylinder head to run slightly cooler than the cylinder block, greatly reducing engine wear.
A Single Overhead Camshaft (SOHC) design uses dual intake valves to deliver the optimal air/fuel mixture for maximum torque and combustion efficiency. In addition, a Multi-Port, Programmed Electronic Fuel Injection system (PGM-FI) accurately controls ignition timing during start-up to provide instant throttle response and outstanding fuel efficiency.
Top-mounted electronics are a standard feature on both engines. The alternator, ignition, and other critical components are mounted near the top of the powerhead to ensure that all are kept cool and dry. By extension, a camshaft-driven, automotive-style oil pump promotes long-term durability of critical engine components.
The BF90 boasts an Engine Alert System that uses audio and visual cues, as well as rpm reduction circuits to alert the operator of conditions which can contribute to engine damage, such as overheating, low oil pressure, and over-revving. A freshwater flushport functions to flush debris and salt water out of the engine, while Honda’s patented 4-Front Corrosion Protection System features a double-sealed, multi-layered paint process – both features extend the life of the outboards in harsh marine environments.