By Charles Plueddeman
New 2010 Outboards from Honda, Suzuki, and Yamaha
These four-stroke upgrades improve the efficiency and lower the weight of the models they're replacing.
Three outboard manufacturers have announced new models for 2010. Honda and Suzuki each have a new 60-hp motor series that represents the next generation of four-stroke design for each company. Yamaha comes with a new 25-hp model that fills a gap in its line.
A significant change for 2010 will be the elimination of the remaining “dirty” carbureted and EFI two-stroke models that Mercury and Yamaha have been selling through Tracker/Bass Pro Shops (Mercury) and builders like Alumacraft (Yamaha). Both companies had banked emissions credits with the EPA that they could use to offset these non-compliant motors (except in California), but new EPA regulations put a cap on emissions that can’t be circumvented with credits. So once January 1, 2010 arrives, the old, smoky two-stroke will begin to fade into history.
The all-new Honda BF60 features much of the same technology that Honda first deployed on its BF90 when it was launched in 2007 (see Boats.com review), including the Boosted Low Speed Torque (BLAST) system for better hole-shot power, Lean Burn Control for enhanced economy, and electronic fuel injection. The BF60 uses a new three-cylinder, 998cc powerhead with a single overhead cam. Honda claims the lightest version of the BF60 has a dry weight (no oil, lube or prop) of just 239 pounds, or about the same as the two-stroke Evinrude E-TEC 60.
The BLAST system is engaged when you “drop the hammer” on the throttle to get out of the hole, advancing the timing just to the point of detonation and delivering a short burst of extra fuel through the injectors. The result is a little added torque. If you advance the throttle gradually, BLAST does not engage. Lean Burn Control helps maximize efficiency at cruising speed by adjusting the air/fuel mixture (using data from the oxygen sensor in the exhaust) to an extra-lean rate, which will not harm the engine at this speed. The engine computer also enables a new trolling speed control, which lets the operator micro-adjust the throttle in 50-rpm increments between 750 and 1000 rpm. This feature is controlled with a dash-mounted switch on remote-control models, or with a switch on the tiller on those models. The tiller holds a new four-lamp warning message screen, and a reversible shift control that can be swapped from the port to starboard side of the tiller. Another clever gizmo on this new Honda is a dash-mounted rudder angle indicator, which will be handy on pontoon boats where the engine is usually out of sight.
The BF60 will be offered in 20-inch and 25-inch shaft lengths, in remote or tiller configurations, all with power trim and tilt. A separate BF60 Power Thrust configuration has a bigger gearcase holding a 2.33:1 gearset designed to handle larger-diameter props than the standard, 2.07:1 ratio. The Power Thrust version also has more charging power, thanks to a 27-amp alternator that delivers 22 amps to the battery, better than the already great 22/17-amp alternator on the standard BF60.
Suzuki also has a new 60-hp motor, the DF60, coming to dealers. This all-new motor will replace the current, four-cylinder, single overhead-cam, 1298cc DF60 with a more category-appropriate, three-cylinder, double overhead-cam, 941cc model. It’s more compact than the new Honda BF60, and with a claimed dry weight of just 229 pounds, the new DF60 is even lighter than that motor and the Evinrude E-TEC 60.
When Suzuki debuted the previous, four-cylinder powerhead in 1998 as a DF60/70, it was a ground-breaking engine that showed the potential of four-stroke outboard power. This new DF60 shows how far the design has come in a decade. Suzuki worked hard on improving its fuel efficiency, with a more sophisticated engine control system and multi-point EFI. Like the Honda, the Suzuki is designed to run very lean when it is not under a heavy load. This motor also has less internal drag – in part because it has one less cylinder – and the oiling system was designed to reduce parasitic loss. Suzuki says it all adds up to enhanced fuel efficiency, and claims that, compared to the previous DF60, the new DF60 burns 40 percent less fuel at trolling speed, 45 percent less at cruising speed, and 20 percent less at full throttle.
Other details include a maintenance-free, oil-bath timing chain located below the powerhead, and the Easy Start System that starts the motor with a quick, single turn of the key. The starter stays engaged until the motor is operating. This also prevents the owner from turning the key to engage the starter when the motor is already running, an issue on other Suzuki motors because they are so quiet. Alternator output is 19 amps, actually less than the 25 amps made by the previous DF60.
Smaller and lighter is also the theme for a new DF9.9A/8A, rated at 9.9 and 8 hp respectively, which has a new 208cc powerhead and at 87 pounds (for the 15-inch, rope-start model) is 10 pounds – a significant 10 percent – lighter than the previous DF9.9. The 8-hp rating is new for Suzuki. Both models are available with a new tiller handle that incorporates shifting on the end of the twist grip, the throttle in the center, and a throttle-friction adjustment in a collar at the base. It’s a design that keeps your hand on the tiller at all times. Electric-start models have a 10 amp alternator. Suzuki will continue to offer the high-thrust DT9.9T with its 302cc displacement, 2.08:1 gear ratio, four-blade prop and standard power trim, a package intended for pushing heavy sailboats, pontoons and skiffs.
Intended to fill the gap between its F20 and F40 models, the new Yamaha F25 will be a nice fit on smaller aluminum fishing boats and compact pontoons.
Its twin-cylinder, 498cc powerhead is essentially half of the four-cylinder, F60 powerhead. The F20 uses the same pistons, connecting rods and valves as that motor, but has a fresh single overhead-cam cylinder head design. The F25 weighs as little as 170 pounds. For comparison, the Mercury 25 FourStroke weighs as little as 157 pounds, and that motor is a 526cc triple-cylinder design that also features electronic fuel injection. The Yamaha F25 has a carburetor, though it’s fitted with Yamaha PrimeStart, an auto-enrichment system that has delivered easy starts on other Yamaha motors. Models so equipped have a new, stronger tiller with a top-mount shifting lever. There’s also a T25 version that comes with a Dual Thrust propeller (designed to provide better thrust in reverse), a larger gearcase, and a 2.42:1 gear ratio that’s lower than the standard 2.08:1 ratio, all designed to help this motor perform better behind a heavy pontoon boat.
Editor’s Note: Charles Plueddeman, our Outboard, Trailer, and PWC Expert, is a former editor at Boating Magazine and contributor to many national publications since 1986.
- Charles Plueddeman is Boats.com's outboard, trailer, and PWC expert. He is a former editor at Boating Magazine and contributor to many national publications since 1986.