Marine News from the Great Lakes

Suzuki Introduces DF350A 350HP V6 4-Stroke Outboard

New Flagship Model Features Innovative Contra-Rotating Propellers, More Exclusive Features

Published: Thursday, November 30, 2017

Suzuki Marine, a leader in 4-stroke outboard technology and performance, is proud to introduce its newest model, the DF350A. At 350 horsepower, this V6 4-stroke is the largest, most powerful outboard Suzuki has built to date. In development for more than three years, it represents a significant milestone in both engineering and design.

“We took the time and effort to build a powerful new outboard that really matches the trend towards bigger boats,” said Gus Blakely, Vice President of Marine Sales for Suzuki Motor of America, Inc. “Whether you’re talking 40-50 foot center consoles or even the new breed of runabouts, deck boats, and cruisers, Suzuki can now deliver the power, performance, and ease of use boat builders and their customers are asking for.”

350 Horsepower And A 12.0:1 Compression Ratio

Suzuki engineers achieved 350 horsepower while still designing a compact, lightweight powerhead. The robust engine displacement of 4.4 liters is matched by a high-performance 12.0:1 compression ratio, the highest ever for a production outboard engine. A unique combination of cool air intake, dual fuel injectors, and a strengthening of the pistons has virtually eliminated engine knock, a typical by-product of high compression engines.

Suzuki Dual Louver System, Direct Air Intake

Suzuki engineers have designed an air intake system that allows the engine to draw in ample fresh air, while separating out water, spray, and moisture. Dual louvers under the hood trap larger water droplets and then moisture as it enters the engine cowling, resulting in zero water intake during testing. In addition, intake air temperatures are, on average, 10° cooler than ambient, providing the combustion chamber with cooler, denser air for a more powerful cycle.

Dual Injectors

Two smaller fuel injectors allow for precise injection of fuel to the center of the combustion chamber, which avoids off-center combustion — a major cause of knocking. In addition, because 100% of the fuel is injected into the cylinder at once, a degree of cooling is also obtained, providing up to 3% additional power without causing knocking.


Advanced Piston Technology

To achieve 350 horsepower, the surface of the piston needs to withstand added forces. In order to assure both performance and long life, Suzuki engineers switched from a standard heat treatment to “shot peening.” Shot peening, a more expensive process, creates fine dimples in the face of the piston that evenly distribute the pressure created during combustion. In addition, the connecting rods and hardware have been strengthened to handle the added loads.

Suzuki Dual Prop System

While contra-rotating propellers are not a new technology, they have never been successfully used on 4-stroke outboard motors until now. The DF350A’s dual propellers provide three key benefits: 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 gearcase could be kept to a minimum, which, in turn, allowed for the design of a sleeker, more hydrodynamic gearcase. Suzuki engineers spent many hours in computer simulation and on the water, knowing that reducing drag underwater would be essential to improving overall boat speed and performance.

Contra-rotating propellers also provide added surface area, for more stability and increased “traction” or grip underwater. (Think of the wide slicks on a drag racer as compared to typical tires.) This results in exceptional acceleration, or hole-shot, truer directional propulsion (eliminating steering torque), better than expected top speeds and incredible reverse thrust. Importantly, these benefits are apparent even on heavier boats with full loads of fuel, gear, and people.

Proven Suzuki Technology

“You can see that our 350A incorporates a lot of innovative new technology, but we’ve been able to utilize the best of our proven 4-stroke technology, as well,” added Blakely. “When we say ‘Ultimate 4-stroke’ we mean it in every way — performance, reliability, dependability, even superior fuel economy.”

The DF350A features Suzuki Precision Control, drive-by-wire throttle and shift controls. Skippers will appreciate smooth shifting, precision control of the throttle, not to mention easier rigging, especially when second stations are involved.

Like Suzuki’s other V6 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 quick acceleration, and improvements in top speed, as well. (It is worth noting that the DF350A can be mounted 27-inches on center, so it will fit on more transoms, and take up less space in twin, triple, and quad installations.)

The DF350A also takes advantage of Suzuki’s Lean Burn Control Technology, for improved fuel economy throughout the entire rpm range, and especially at cruising speed. Like all Suzuki 4-stroke outboards, the DF350A is extraordinarily quiet at idle.

As you can see, the development of this new outboard has been driven by Suzuki’s belief that it is important to provide the market with more than just horsepower. While power and speed are critical factors, the added dimensions of efficiency, reliability, and stability make the DF350A the Ultimate 4-Stroke Outboard.

“Suzuki is committed to providing all of our customers with the ‘ultimate’ experience on the water,” said Blakely. “This new 350 horsepower outboard has a few tricks up its sleeve, and it’s ready to take on all comers. If you’re looking for the best, you don’t have to look any further than Suzuki.”

For more information on Suzuki’s new DF350A or their full line of 4-stroke outboard motors, now from 2.5 to 350 horsepower, please visit


• Shaft Length X: 25” / 638mm XX: 30” / 762mm
• Starting System Electric
• Engine Type V6 – 55 ̊ DOHC 24-Valve
• Weight X: 727 lbs / 330 kg XX: 747 lbs / 339 kg
• Valve Train Drive Chain with Variable Valve Timing
• Fuel Delivery System Electronic Fuel Injection
• No. of Cylinders 6
• Displacement 267.9 / 4.390 liters
• Bore x Stroke 3.74” x 3.82” / 98mm x 97mm
• Maximum Output 350 HP / 257.4 kW
• Full Throttle Operating Range 5,700 – 6,300 rpm
• Steering Remote
• Oil Pan Capacity 8.5 quarts / 8.0 liters
• Ignition System Fully-transistorized
• Alternator 12V 54A
• Engine Mounting Shear Mount
• Trim Method Power Trim and Tilt
• Gear Ratio 2.29:1
• Gear Shift F-N-R (Drive By Wire)
• Exhaust Through Prop Exhaust
• Propeller Selection Front: 3 x 15.5 x 19.5 – 31.5
• (All Props Are 3-Blade) Rear: 3 x 15.5 x 19.5 – 31.5


tags: Engines


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