Suzuki DF350A Specifications
| Engine Model: Suzuki DF350A |
| Engine Type: 4-stroke 6-cylinder DOHC 24-valve gasoline outboard engine |
| Total Displacement: 267.9 cu.in (4.4 L) |
| Rated Engine Power: 350 Hp (257.4 kW) at 6000 rpm |
| Fuel System: Multi point sequential electronic fuel injection |
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The Suzuki DF350A is a groundbreaking outboard
that redefines expectations for high-Hp marine propulsion. Its most
distinctive feature is the contra-rotating dual propeller system, which
distributes engine torque evenly over two propellers, reducing torque
per propeller and enabling a smaller, more hydrodynamic gearcase design
that moves through the water with less resistance.
The all-new 4.4-liter V6 powerhead features a high 12:1 compression
ratio and requires 94 RON fuel to extract maximum power, delivering
exceptional hole-shot with virtually no bow rise and remarkable lifting
power that instantly brings heavy boats on plane.
Advanced technologies including the Suzuki Lean Burn Control System,
Precision Control drive-by-wire, and Variable Valve Timing with 30
degrees of adjustment work in harmony to provide smooth, immediate power
delivery across the entire operating range. Weighing only 330 kg, the
DF350A proves that immense power does not require excessive baggage.
Engine Model: Suzuki DF350A
Engine Type: 4-Stroke, 55° V6, DOHC (Double Overhead Camshaft), 24-Valve
Number of Cylinders: 6
Valve Train Drive: Self-adjusting oil-bathed timing chain with automatic
hydraulic tensioner and Variable Valve Timing (30-degree adjustment
range)
Bore and Stroke: 98.0 mm x 97.0 mm (3.86 in x 3.82 in)
Piston Displacement: 4390 cc (267.9 cu. in)
Maximum Output: 257.4 kW (350 Hp)
Full Throttle Operating Range: 5700-6300 rpm
Fuel Delivery System: Multi-Point Sequential Electronic Fuel Injection
with Dual Injectors (dual 10-hole injectors), Lean Burn Control, and
Oxygen Sensor Feedback
Alternator: 12V 54A
Trim Method: Power Trim and Tilt
Gear Ratio: 2.29:1 with 2-Stage Gear Reduction
Gear Shift: F-N-R (Forward-Neutral-Reverse) via Suzuki Precision Control
Drive-by-Wire
Control System: Suzuki Precision Control (Digital Drive-by-Wire)
Exhaust: Through Prop Hub Exhaust
Propeller Selection: 12"-31.5" pitch, Contra-Rotating Dual Propellers
(Front and Rear, both 3-blade type, 15" diameter)
Starting System: Electric with Suzuki Easy Start System
Ignition System: Full-transistor Solid State Direct Ignition
Engine Lubrication: Trochoid pump pressure lubrication
Engine Oil Capacity: 8.0 L (8.5/7.0 US/Imp. qt.)
Gear Oil Capacity: 3.2 L (3.4/2.8 US/Imp. qt.)
Fuel Type: Alcohol-free unleaded gasoline
Minimum Fuel Octane Rating: 94 (Research method)
Spark Plugs: NGK ILZKR7D8
Spark Plug Gap: Standard: 0.7-0.8 mm (0.028-0.031 in)
CARB Emissions Rating: 3-Star Ultra-Low
The DF350A is built around an all-new 4.4-liter V6 powerhead with a
narrow 55-degree bank angle, making it the largest displacement V6
outboard available and providing the tremendous torque essential for
pushing the largest vessels. The block features an exceptionally high
compression ratio of 12:1, delivering breathtaking power output while
requiring 94 RON fuel for maximum performance.
To withstand the extraordinary forces generated by this compression
ratio, the engine utilizes shot-peened slipper pistons that are
extremely strong yet lightweight. Intake and exhaust ports have been
completely reshaped to optimize airflow for the high-output powerhead.
The powerhead incorporates a DOHC 24-valve configuration with an
advanced Variable Valve Timing (VVT) system that has been significantly
enhanced compared to previous generations. The range of adjustment has
been increased to 30 degrees from the previous 20 degrees, allowing for
even greater optimization of valve timing across the entire operating
range. This provides the additional torque needed for accelerating in
the low to mid-range while maintaining maximum power at high rpm.
The offset driveshaft design positions the crankshaft in front of the
driveshaft, moving the outboard's center of gravity forward. This
configuration makes the outboard more compact, improves weight
distribution on the boat's transom, and significantly reduces vibration
by moving the engine's axis of inertia up over the upper engine mount.
The powerhead utilizes a left-hand rotation design to maintain
conventional right-hand driveshaft output through the gear system.
The DF350A's fuel system represents the zenith of Suzuki fuel delivery
technology with its Dual Injector System, utilizing two 10-hole
injectors per cylinder to provide immense precision, superior
atomization, and exceptional fuel efficiency. This advanced system
delivers a fine mist of highly atomized fuel into the combustion
chamber, ensuring complete combustion for maximum power output and
reduced emissions.
The Suzuki Lean Burn Control System supplies the appropriate air-fuel
mixture depending on navigation conditions, using an O2 sensor feedback
loop to optimize efficiency across all speed ranges, particularly at
cruising speeds. This combination with the Suzuki Precision Control
electronic throttle system offers exceptional fuel economy for an engine
of this power output.
The Knock Sensor continuously monitors combustion to provide optimized
performance while maximizing power output and increasing engine
durability. The large displacement powerhead demands substantial air
volume, supplied through the innovative Dual Louver System.
The DF350A employs a trochoid pump pressure lubrication system to ensure
consistent pressurized oil delivery to all critical engine components,
including the crankshaft, connecting rods, and valve train with its
advanced VVT components.
The engine has a substantial oil capacity of 8.0 liters. Proper
lubrication maintenance, including regular oil changes with high-quality
NMMA FC-W certified 4-stroke outboard oil, is essential for long-term
durability.
Cooling efficiency is enhanced by a dual water inlet system, a critical
feature for high-performance operation. The engine's cooling system
relies on water supplied through two water inlets located on the lower
unit, with inlets positioned at the gearcase tip to take advantage of
dynamic pressure for stable water suction at very high speeds. The
secondary inlet positioned lower allows the engine to operate
effectively in shallow water conditions.
For post-operation maintenance, the Fresh Water Flushing System allows
easy connection of a garden hose to rinse salt, sand, and other debris
from the cooling passages, protecting the engine from corrosion.
| Mid Section and Lower Unit |
The mid-section and lower unit of the DF350A house its most
revolutionary features. The Suzuki Dual Prop System spins two propellers
rotating in opposite directions on a single engine, providing more grip
underwater and distributing engine torque evenly over two propellers.
This configuration reduces torque per propeller, allowing gear diameter
to be reduced and enabling a smaller, more hydrodynamic gearcase design
that moves through the water with less resistance.
The newly designed gearcase reduces frontal projected area by 4 percent
while increasing top speed by more than 2 percent according to Suzuki
in-house testing. The shifting mechanism is strategically located in the
upper area of the gearcase to maintain compact dimensions. The
contra-rotating configuration produces exceptional stability when
driving straight by eliminating the lateral forces associated with
single propeller designs, while also generating powerful reverse thrust
for superior maneuverability.
The 2-Stage Gear Reduction system incorporates the offset driveshaft
with a first stage reduction between the crankshaft and drive shaft, and
a second stage reduction inside the gear case. This design makes the
2.29:1 gear ratio possible, allowing the engine to turn large diameter
propellers with tremendous power for quick acceleration and high
propulsive efficiency even under heavy loads.
The Power Trim and Tilt system provides hydraulic control over the
outboard's angle, allowing the operator to adjust boat trim for optimal
performance, fuel efficiency, and ride comfort. Proper trim angle
adjustment is critical for maintaining steering stability and good
performance. If the trim angle is too small, the boat may "plow" or "bow
steer," while excessive trim angle may cause the boat to "chine walk" or
"porpoise," resulting in loss of steering control.
The Tilt Limit System prevents the outboard from tilting beyond a
selected angle. When the motor is tilted beyond the maximum trim
position, the swivel bracket loses side support from the clamp bracket,
and operation above 1500 r/min should be avoided.
The DF350A is designed specifically for the Suzuki Dual Prop System
featuring contra-rotating propellers with a three-blade front and
three-blade rear configuration, both with 15-inch diameter. The
recommended propeller pitch selection ranges from 19.5 inches to 28.5
inches, with available pitches including 19.5, 21, 22.5, 24, 25.5, 27,
and 28.5 inches.
The front and rear propellers must be the same number of blades,
diameter, and pitch when installed, as using an improper combination can
cause lower unit damage. The Watergrip Propeller, featuring a new
interchangeable square-shaped bush, offers efficient conversion of
engine power to propulsion resulting in better grip and performance.
The increased total blade area compared to a single 16-inch propeller
provides significantly more water "traction" to lift heavy boats on
plane and harness the substantial torque of the 350HP powerhead.
Transom Height (Extra Long Shaft - X): 635 mm (25 in)
Transom Height (Extra-Extra Long Shaft - XX): 762 mm (30 in)
Dry Weight (Extra Long Shaft - X): 330 kg (727 lbs)
Dry Weight (Extra-Extra Long Shaft - XX): 339 kg (747 lbs)
Engine Mounting: Shear mount rubber damper system
Engine Oil Capacity: 8.0 L (8.5 US qt.) with filter
Recommended Oil: High-quality 4-stroke outboard oil, NMMA FC-W certified
Gear Oil Capacity: 3.2 L (3.4 US qt.) with regular change intervals
Spark Plugs: NGK ILZKR7D8
Spark Plug Gap: Standard: 0.7-0.8 mm (0.028-0.031 in)
Valve Clearance (Intake): 0.23-0.27 mm (0.009-0.011 in) (cold)
Valve Clearance (Exhaust): 0.33-0.37 mm (0.013-0.015 in) (cold)
Battery Requirement: Minimum 1000 Marine Cranking A (MCA), 800 Cold
Cranking A (CCA), or 180 Reserve Capacity minutes
Connecting Rod Nuts: 23 Nm (16.5 lb-ft) plus 90-deg turn
Crankshaft Bearing Cap Bolt: 68 Nm (49.0 lb-ft)
Crankcase Bolts (various): 48 Nm (34.5 lb-ft), 25 Nm (18.0 lb-ft), 22 Nm
(16.0 lb-ft) plus 90-deg turn
Oil Filter Stand Bolt: 11 Nm (8.0 lb-ft)
The Suzuki DF350A is engineered specifically for the most demanding
applications requiring maximum power and thrust, particularly for large
vessels and professional operations. Large Offshore Sports Fishing
Boats: Ideal for large center consoles and sportfishing boats in the
30-40 foot range, providing the immense power needed for quick planing,
exceptional handling in offshore conditions, and the ability to reach
speeds approaching 60 mph.
Catamarans and Large Cruisers: Provides the muscle needed for cruising
catamarans, express cruisers, and other large vessels, with twin
installations offering remarkable performance and range. Commercial
Applications: Built for everyday use in commercial operations where
reliability, durability, and fuel efficiency are paramount for pushing
heavy loads. The engine's robust construction has earned it recognition
from commercial operators such as Sea Start and Solent RIB Charter.
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