Mid-Engine Racer
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By: Alan Jones
August, 2009
By now, most people are aware of the benefits of four-stroke power: The engines are quiet, clean-burning and reliable. Of course, the word on the street is that they’re quite a bit heavier and don’t have anywhere near the snappy acceleration of a direct-injected two-stroke. But American Honda Motor Co. Inc., which is celebrating its 50th year of bringing four-stroke power to the U.S., hopes to erase this way of thinking with the new BF60 EFI and the High Thrust model called the BFP60 EFI. A distinctive new styling package called the “Wedge Shape” that’s said to have been based on the shape of a killer whale makes the BF60 instantly recognizable.
Lighten up, man
Most people probably believe the lightest outboard in the 60 hp class is the Evinrude E-TEC 60 direct-injected two-stroke, which weighs a svelte 240 pounds, but the Honda BF60 tips the scales 1 pound lighter at 239 pounds, making it one of the lightest engines in its class. Honda doesn’t do this by making components less robust, but by substituting components like the air intake, which is normally made from cast iron, and replacing it with a lightweight resin composite Mikuni model. Another weight savings is gleaned from the strong, yet light aluminum transom bracket.
Blast from the future
For small fishing boats that ply the shallows, getting on plane quickly is a necessity and has traditionally been one of the selling points of two-stroke technology, but Honda seeks to negate that advantage with a system called BLAST (Boosted Low Speed Torque). This technology is activated when the driver jams the throttle like an escaping bank robber. This advances the spark aggressively and keeps the timing on the edge of the envelope, keeping it dialed in to within 1 degree of the knock limit. This ensures the more potent air/fuel mixture that the engine’s ECU, the computerized brain, has ordered will be fully burned, giving it a strong “blast” of power to get you on plane quickly.
We confirmed the effectiveness of BLAST during a test on Lake Lanier, north of Atlanta on a 16-foot aluminum Starcraft fishing boat. With this modest amount of power and two big guys on board, we zipped onto plane in 3.8 seconds. BLAST continued kicking the transom in the seat of the pants until we reached 25 mph in 7.8 seconds, then we backed off the throttle to settle into a cruise speed at 4000 rpm.
Lean on me
Now that the Honda has blasted you onto plane, the mission is to deliver the best fuel economy possible and it does so in a unique way. Light piston aircraft have always used an adjustable air/fuel mixture after takeoff when they reach a higher altitude, where the air is less dense and offers less resistance. Honda uses the same approach when the engine’s load is reduced after takeoff and the power needs are reduced. Called the Lean Burn Control system, the volume of fuel in the mix is decreased, saving you money at the pump.
In our test, we found the Starcraft’s sweet spot to be at 19.2 mph at 3500 rpm. We were burning a paltry 1.6 gph, according to information from the ECM, not a paddlewheel as is the case on some other engines’ fuel-monitoring systems. This translates to 12 mpg, which might be better than the truck that brought the boat to the lake. The most we could get the Honda BF60 to burn at wide-open throttle was 5.4 gph, which at 37.9 mph still yielded better than 7 mpg. This performance puts Honda at the top of its class in fuel economy.
Live long and prosper
Honda maximizes the BF60’s long life by equipping it with a host of corrosion-fighting tools. In addition to a five-part external barrier, internal passages are coated with a corrosion-resistant paint. The engine also features sacrificial anodes that are strategically placed to prevent galvanic corrosion.