Product Review: Suzuki DF350A Four-Stroke V6 - The Fisherman

Product Review: Suzuki DF350A Four-Stroke V6

Suzuki

I had a chance to put about 20 hours of hard and fast (40 to 50 mph) ocean running time on Suzuki’s DF350As down in Key West back in 2020. We ran 150 to 175 miles a day on a 36 Yellowfin CC and a 35 Contender CC with Capt. RT Trosset (239 IGFA world records) and his son Capt. Chris at the helm of each boat. The speed, fuel efficiency, traction and smooth, reliable performance of these contra-rotating, twin-prop powerplants literally blew me away.

The DF350A provides superior “grip” on the water when you hit the electronic throttle. This translates to superior performance, with improved hole shots, stronger mid-range acceleration, greater top-end speed and enhanced low-speed maneuvering. With the engine’s power distributed over six blades, rather than three, Suzuki reduced the size of the gears and created a sleek, hydrodynamic lower unit that slices through the water with minimum drag. This increased propeller blade surface area and contra-rotating action also delivers exceptional acceleration while eliminating steering torque and providing incredible reverse thrust, an especially important feature for docking and other close-quarter maneuvers.

And when you hit the throttle when underway, the push at the prop is a really noticeable. The DF350A features an offset driveshaft engine layout, with two-stage gear reduction (2.29:1) for plenty of low-end torque without sacrificing top-end performance.

The DF350A’s robust 4.4-liter displacement features a radical 12:1 compression ratio and dual fuel injectors per cylinder for optimum performance and efficiency, requiring 89 octane gasoline to make things happen. By using two smaller fuel injectors, Suzuki delivers a precise amount of fuel to the center of the combustion chamber, improving atomization and avoiding off-center combustion, a common cause of engine knock. Injecting 100 percent of the fuel into the cylinder at once also keeps the fuel cool, providing up to 3 percent additional power. A dual-louver, direct air intake system on the DF350A helps the engine breath freely for optimum performance while separating out water, spray and moisture for improved reliability.

Suzuki’s proven Lean Burn Control Technology helps ensure optimum fuel efficiency at cruising speed and across the entire rpm range. The narrow bank 55-degree V6 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. It’s available in either black or white.

Suzuki

Multiple Power Options

Suzuki’s flagship DF350A can be used on boats ranging from 23 to 45 feet in single, twin, triple and quad applications. If your vessel’s transom can handle the weight (727-lbs XL/747-lbs XXL) and the horsepower rating, Suzuki’s 350A will deliver the sea ponies with a minimal feeding bill. Factory tests on a SeaPro 239CC outfitted with a single DF350A indicated that this deep-vee center console hit a top speed of 54.2 mph at 6,200 rpm, with optimum cruise occurring at 3500 revs, where she registered 27.5 mph on the GPS, drinking only 8.2 gph, for a net of 3.35 mpg. That’s fuel economy that many 21-footers would envy! Bumping the electronic throttle up to 4,000 and 4,500 rpm, produced 33.7 mph/2.98 mpg and 39 mph/2.73 mpg performance numbers respectively, so there’s minimal penalty in the fuel efficiency department if you need to bump it up.

Going with twin DF350As on the transom, factory tests on a Southport 33CC generated a top speed of 54 mph at 6250 revs, with an optimum cruise of 26.8 mph at 3,500 rpm burning 18.6 gph, which translated to 1.44 mpg. Accelerating to 32.3 mpg at 4,000 reduced fuel economy somewhat to 1.37 mpg, but is an equitable trade-off to get to your fishing spot a bit faster. Another factory test on a Yellowfin 36 Offshore employing triple DF350As showed a top speed of 67.1 mph at wide open throttle (6,250 rpm), with an optimum cruising speed of 31.3 mph at only 3,000 netting 1.48 mpg.

Suzuki Marine USA, LLC has introduced a new Five-Year Limited Warranty on all of its new outboard motors. This significantly longer factory-backed coverage (Suzuki’s previous standard Limited Warranty was 3 years) applies to all motors purchased for pleasure use, with the warranty registered on or after April 1, 2021.

Suzuki also announced that the company is proceeding with testing of its innovative Micro-Plastics Filter Device developed exclusively for use on outboard motors. This one-of-a-kind system integrates with the engine’s cooling system, allowing a specially designed filter screen to collect micro-plastic pollution as owners drive their boats. Suzuki is testing this device on boats around the world, with an eye towards making boaters part of the solution to the global challenge of micro-plastics pollution. The plan is to begin introducing this as an option on some of its outboard lineup for the 2022 model year. For more information, visit www.suzukimarine.com.