Over the course of our history in the marine industry, Suzuki has been recognised for having the most innovative new 4-stroke outboards eight times by the National Marine Manufacturers Association (NMMA).

This recognition for innovation has also been coupled with many firsts, including the first fuel injected 4-stroke outboards in 1997, the first 250 horsepower 4-stroke outboard in 2003 and the world’s first 300 horsepower 4-stroke outboard in 2006.

Introducing the next milestone in our rich history, the 350 horsepower DF350A, Suzuki’s Ultimate Outboard Motor.

GEKI: PARTING SEAS

A Force to Match the Power of Nature and the Sea Representing Suzuki’s Identity and Heritage A Symbol of Our Passion and Commitment to the Ultimate in Marine Innovation.

HIGHEST COMPRESSION RATIO EVER

In order to achieve the engineering target of producing 80 horsepower per litre from a 4.4L V6 engine, a 12.0:1 compression ratio was employed, the highest compression ratio ever featured on a production outboard engine. To avoid ‘knocking’ which can be a typical byproduct of a high compression engine, advanced systems were developed to mix cooler air with well-atomised fuel providing optimal conditions for a complete and controlled combustion.

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, 10º cooler than ambient, providing the combustion chamber with cooler, denser air for a more powerful cycle.

DUAL INJECTORS FOR INCREASED COOLING AND POWER

Two, smaller fuel injectors allow for precise injection of fuel to the centre of the combustion chamber, which avoids off-centre 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.

CONTRA-ROTATING PROPELLER

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 gear case could be kept to a minimum, which in turn allow for a sleeker, more hydrodynamic gearcase design. 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. 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.

FEATURES

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 is a more expensive process that 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.

PROPELLER BLADE DESIGN

A three-blade front/three-blade back propeller set-up was developed that provided improved performance on the water. This new set up provided not only the highest recorded speeds for the DF350A, but also delivered incredible acceleration, even under heavy load and at high rotation speeds.

DUAL WATER INTAKES

On the DF350A, the best results were achieved when the main intake was positioned at the front of the gear case, with the secondary intake located just above the skeg. This was our ultimate solution to arranging the main and sub intakes as far apart from each other as possible, and designing them to ensure a reliable amount of cooling water, especially at high speeds.

STRONGER REVERSE THRUST

The gear material was changed and heat treatment was added to endure the added thrust and inertial mass from the reverse thrust, which was stronger on a contra-rotating propeller. In addition, the reverse gear was moved above the cavitation plate and the position of the lower engine mounts was modified from parallel to V-shape to fit the reverse gear above the cavitation plate.

SUZUKI SELECTIVE ROTATION

Normally, when using multiple outboards a combination of standard and counter-rotating engines is mounted. The Suzuki Selective Rotation, available on our AP series outboards, eliminates the need for different models, as any model can be easily programmed to run in either direction. The DF350A’s contra-rotating propeller technology takes this process one step further by eliminating steering torque and maximizing true and straight propulsion forces.

LEAN BURN

Suzuki’s innovative Lean Burn Control System was first introduced on the DF90A/80A/70A to great acclaim. The system predicts fuel needs according to operating conditions, allowing the engine to run on a leaner, more efficient air fuel ratio. It delivers its benefits over a wide operating range, providing significant improvements in fuel economy from low-speed operation into the cruising range. In combination with Suzuki Precision Control electronic throttle and shift system, the operator can precisely, and smoothly, increase or decrease engine RPM for significantly improved fuel economy.

PRECISION CONTROL

This technologically advanced system is a computer-based drive-by-wire control system that eliminates the friction and resistance of mechanical control cables. Operation is smooth and precise with crisp, immediate shifting that is most evident in the low rpm range and when manoeuvring around the marina and in close quarters. The system is configurable for single, twin, triple, or quad installations, and for dual stations.

VARIABLE VALVE TIMING (VVT)

Suzuki’s engineers designed the 4.4-liter V6 engine with an aggressive cam profile that delivers maximum output and performance at high rpm. In coupling this cam profile with Suzuki’s advanced Variable Valve Timing (VVT), the DF350A delivers the additional torque that outboards need for accelerating in the low to midrange. VVT achieves this by adjusting the timing of the intake valves, allowing them to open before the exhaust valves are fully closed, creating a momentary overlap in the timing where both sets of valves are open. Using VVT, this overlap can be increased or decreased by altering intake timing with the camshaft resulting in optimum timing for low and mid-range operation.

SUZUKI TROLL MODE SYSTEM

Suzuki’s Trolling Mode system provides finer control over engine speed at low rpms to keep your boat moving at a constant speed while trolling. When the system is engaged, revs are controlled with an independent control switch that adjusts engine revs in 50rpm increments over a range spanning from idle to 1,200rpm. The system includes a control switch, which can be mounted nearly anywhere on the console, and a tachometer, and is compatible with Suzuki’s SMIS digital gauges or the dual scale analogue gauges.

SELF-ADJUSTING TIMING CHAIN

The timing chain runs in an oil-bath, so it never needs lubricating, and is equipped with an automatic hydraulic tensioner, so it remains properly adjusted at all times. Simple, effective and maintenance-free.

ANTI CORROSION FINISH

Suzuki’s Anti-Corrosion Finish is specially formulated to increase the durability of the engine and help protect parts of the aluminium exterior that are constantly exposed to fresh and saltwater. This advanced finish offers maximum bonding to the outboard’s aluminium surface, creating an effective treatment against corrosion.

2-STAGE GEAR REDUCTION

The DF350A outboard also incorporates a 2-Stage Gear Reduction which results in a large reduction gear ratio. It delivers powerful torque for quick acceleration and great top-end speed.

SPECIFICATIONS