SUZUKI DF350A OUTBOARD - The Fisherman


Suzuki’s new DF350A V-6 four-stroke outboard is a game changer that will certainly make both coastal anglers and competitors take notice. According to Suzuki USA’s VP of Sales Gus Blakely, “The DF350A incorporates a lot of innovative new technology, enabling us to utilize the best of our proven four-stroke technology to achieve the magic combination of performance, reliability, dependability and even superior fuel economy.”

The DF350A features Suzuki’s proven Precision Control, drive-by-wire throttle and shift controls, which insure smooth shifting, precise control of the throttle position and easier rigging. Like Suzuki’s other V-6 outboards, the DF350A features Suzuki’s offset driveshaft engine layout, which allows for a more compact outboard and two-stage gear reduction. Two-stage gear reduction provides a larger reduction gear ratio (2.29:1) and more torque for both quick acceleration and improvements in top speed. The narrow bank 55-degree V-6 design of the DF350A allows these powerful four-strokes to be mounted on relatively compact 27-inch centers, so it will fit on more transoms and take up less space in twin, triple and quad installations.

The Suzuki engineers broke new ground with the DF350A’s lower unit. While contra-rotating propellers are not a new technology, they have never been successfully used on four-stroke outboard motors until now. The DF350A’s dual propellers provide three key benefits, specifically compact size, increased stability and greater traction. By distributing the power of the engine over six blades, instead of just three, the size of the gears and gear case is kept to a minimum, which in turn allows for the design of sleeker, more hydrodynamic gear case. Suzuki engineers knew that reducing underwater drag would be essential to improving overall boat speed and performance. Contra-rotating propellers also provide added surface area, which results in rapid acceleration, quick hole-shots, more predictable directional propulsion, a reduction in steering torque, increased top speeds and impressive reverse thrust. According to Suzuki’s initial field tests, these benefits are apparent even on heavier boats with full loads of fuel, gear and people. Dual water intakes located at the leading edge of the gear case bullet and on either side of the skeg insure that a constant flow of cooling water gets to the powerhead to keep things cool during those long days offshore.

The powerhead is yet another area of technological innovation for the DF350A, with a hefty 12:1 compression ratio, 4.4-liter displacement, dual overhead cam (DOHC) arrangement for its 32-valve design (two intake and two exhaust valves per cylinder) and twin injectors for each of the six-pack of internal combustion chambers. A pair of smaller fuel injectors allows for a more precise injection of fuel to the center of the combustion chamber, avoiding off-center combustion, which is a major cause of knocking. And since 100% of the fuel is injected into the cylinder at once, add cooling is also achieved, which boosts power. To achieve 350 sea ponies from a relatively small 4.4L engine block, the surface of the pistons were changed to withstand these added forces. In addition, the connecting rods and hardware have been strengthened to handle these added loads.

Suzuki engineers have also designed a new air intake system on the DF350A that allows this four-stroke to draw in substantial amounts of fresh air, while separating out water, spray and moisture. Dual louvers under the hood trap and divert water droplets and moisture as they enter the engine cowling, resulting in zero water intake during operation. In addition, intake air temperatures have been reduced by an average of 10-degrees compared to the outside ambient environment, providing the combustion chamber with cooler, denser air for a more forceful power stroke.

Suzuki has a real winner with their new DF350A four-stroke and it should find its way on the transoms of a number of inshore and offshore boats in the coming months.