HONDA BF250 FOUR-STROKE V-6 OUTBOARD
The exciting performance, power and reliability of the new BF250 four-stroke outboard engine are the result of several exclusive Honda Marine technological features. The BF250 is a high-performance 3.6L VTEC engine that incorporates technological advancements from both Honda’s automotive and marine outboard engine lines. For example, when designing the BF250, Honda engineers increased the stroke of the existing Honda Odyssey car engine, expanding its displacement to 3.6 liters. The result is a new outboard model with excellent performance, improved fuel economy, more power and increased reliability that offers even more displacement than Honda’s former flagship model, the 3.5L BF225.
Integrated into the BF250 design is Honda’s Variable Valve Timing and Lift Electronic Control (a.k.a. VTEC for short). First debuted in the high-performance Acura NSX sports car, VTEC technology also is featured in the designs of the Honda Marine BF225, BF150 and BF90 engines, providing all of these models with a unique blend of power, torque, and efficiency at any speed. VTEC works to vary the lift and duration of the intake valve opening to deliver optimal performance at both low and high rpm, resulting in peak performance at all speeds. The technology provides a broad, flat torque curve and smooth power delivery throughout the engine’s entire operating range, allowing the operator to enjoy both outstanding performance and impressive fuel economy.
The Honda BF250 engine incorporates the Boosted Low Speed Torque (BLAST) System which dramatically improves holeshot acceleration 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 (off the line acceleration) 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 improved fuel efficiency.
The new BF250 also incorporates the world’s first marine direct air dual circuit induction system of its type on a production outboard. The primary circuit draws air into the front and around critical engine components and a top-mounted cooling fan draws cooling air over the alternator. The second circuit routes cool air from the upper intake vents, removes moisture, and then inducts it into the throttle body. This system provides for cooler, denser air for better combustion than conventional under-cowl induction systems. The design of the variable air intake system on the Honda BF250 also includes a large air-intake silencer that reduces noise. The silencing effect results from a chamber being added to the intake passage, causing sound waves to interfere with one another, creating a side branch effect that quiets noise.
Honda four-strokes have always been known for sipping fuel through a very thin straw, even at higher rpms and fast lane cruising speeds and the new BF250 is no exception to that rule. Recent factory tests hitched to the transom of a Carolina Skiff 250LX Bay Runner support this point yet again. With a bare hull weight of 2,800 pounds, a half tank of fuel, plenty of gear and two people aboard, the combination of the 245 Bay Runner powered by the Honda BF250 hit a top speed of 50 mph at 6,200 rpm, spinning a Solas 18-inch pitch three-blade SS prop. Dialing it down to realistic cruising speeds, the Honda really showed its stuff, loafing along at 3,500 rpm and hitting an impressive 25 mph on the GPS navigator while only using 5.2 gallons of fuel per hour. For anyone who’s not a math major, this translates to 4.9 mpg, which is a great benchmark for a 24.5-footer with an 8-1/2- foot beam. Advancing the throttle to 4-grand, she’ll turn 29.5 mph at 7.4 gph for a net of 4 mpg, which is still a number that few competitive hull and power combinations can match. With the digital tach indicating 4,500 revs, the GPS shows 33 mph at 10.9 gph, for 3 mpg. If the afternoon wind chop is getting you down, you can back her off and still hold plane at only 3-grand, getting 20.5 mph at a stingy 3.9 gph for 5.3 mpg. This exceptional fuel economy also translates proportionately if you are running a larger centre console in the 27- to 31-foot range and require twin powerplants.
Engine Type- SOHC, 24-valve, 60-degree V6 four-stroke
Displacement- 219 cubic inches (3.6-liter)
Bore & Stroke- 89mm x 96mm
Rated Power- 250 HP @ 5800 rpm
Full Throttle Range- 5300-6300 rpm
Fuel Delivery- programmed fuel injection
Gear Ratio- 2.00:1
Alternator- 90-amp (battery charging power @ 60-amps)
Models- L (20-inch); XL (25-inch); and XXL (30-inch) shaft lengths
Dry Weight- 600 to 622 lbs, depending on the model