Suzuki DF300B Specifications
| Engine Model: Suzuki DF300B |
| Engine Type: 4-stroke 6-cylinder DOHC 24-valve gasoline outboard engine |
| Total Displacement: 267.9 cu.in (4.4 L) |
| Rated Engine Power: 300 Hp (220.7 kW) at 6000 rpm |
| Fuel System: Multi point sequential electronic fuel injection |
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The Suzuki DF300B is a technological
masterpiece that redefines what a 300 Hp outboard can achieve. Built
around the same large-displacement 4.4-liter V6 block as the higher-Hp
DF325A and DF350A models, it delivers unparalleled torque for its class.
The revolutionary contra-rotating dual propeller system provides
superior water grip, distributing engine torque evenly across two
propellers to reduce individual propeller load while enabling a more
hydrodynamic gearcase design. Engineered to run on 91 RON unleaded fuel
with a 10.5:1 compression ratio, the DF300B incorporates Suzuki's Lean
Burn Control System for impressive fuel economy.
With features like the Dual Louver direct air intake system, dual water
inlets for enhanced cooling, and the Suzuki Precision Control
drive-by-wire system, this outboard delivers the perfect balance of
awesome power, outstanding efficiency, and trusted reliability for the
most demanding applications.
Engine Model: Suzuki DF300B
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
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: 220.7 kW (300 Hp)
Full Throttle Operating Range: 5300-6300 rpm
Fuel Delivery System: Multi-Point Sequential Electronic Fuel Injection
with Dual Injectors, Lean Burn, and Oxygen Sensor Feedback
Alternator: 12V 54A
Trim Method: Power Trim and Tilt
Gear Ratio: 2.29:1
Gear Shift: F-N-R (Forward-Neutral-Reverse) via Suzuki Precision Control
Control System: Suzuki Precision Control (Drive-by-Wire)
Exhaust: Through Prop Hub Exhaust
Propeller Selection: 12"-31.5" pitch, Contra-Rotating Dual Propellers
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: 91 (Research method)
Spark Plugs: NGK ILZKR7D8
CARB Emissions Rating: 3-Star Ultra-Low
The DF300B is built around a potent 4.4-liter V6 powerhead with a narrow
55-degree bank angle, making it the largest displacement V6 outboard in
its class. This substantial displacement provides the tremendous torque
essential for pushing heavy loads and large vessels efficiently.
The block features strengthened forged pistons with advanced surface
treatments including shot peening, which creates fine dimples on the
piston surface to evenly distribute combustion pressure and withstand
the higher forces generated by the 10.5:1 compression ratio.
The powerhead incorporates a DOHC 24-valve configuration for optimal
airflow and combustion efficiency. A self-adjusting oil-bathed timing
chain with automatic hydraulic tensioner drives the camshafts, providing
maintenance-free operation for the engine's lifetime. Variable Valve
Timing (VVT) controls the opening and closing timing of the intake
valves depending on engine operation, offering smooth, powerful torque
and providing tremendous acceleration across all speed ranges.
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 DF300B's fuel system represents a significant advancement with its
Dual Injector System, which uses two smaller injectors per cylinder to
provide immense precision, improved atomization, and increased fuel
efficiency. Injecting fuel achieves two critical functions: atomizing
the fuel for combustion and cooling the cylinder. The dual injector
design ensures complete fuel injection at precisely the right time and
angle for optimal power and cooling.
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 improved fuel economy across a wide
operating range. The Knock Sensor monitors combustion to provide
optimized performance while maximizing power output and increasing
engine durability.
The DF300B 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 VVT
components. The engine has an oil capacity of 8.0 liters.
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 where conventional outboards have only one. This design increases
water flow, providing better cooling performance especially at high
speeds.
The DF300B features water inlets on the tip of the gearcase, which helps
maintain water suction even when dynamic pressure is created by the
gearcase moving through the water at high speeds. 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 DF300B 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 six blades instead
of three. This configuration reduces torque per propeller, allowing gear
diameter to be reduced and enabling a smaller, more hydrodynamic
gearcase design.
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 advanced gearcase design utilizes computational fluid dynamics to
minimize resistance while providing highly efficient water flow to the
propellers. The contra-rotating propeller configuration produces
exceptional stability when driving straight by eliminating the lateral
forces associated with single propeller designs, while also generating
powerful reverse thrust for greater maneuverability.
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. The Tilt Limit System
prevents the outboard from tilting beyond a selected angle, protecting
both the engine and boat from damage due to excessive tilting.
For shallow water operation, the motor can be tilted beyond the normal
trim angle, but operation should be restricted to slow speeds below 1500
r/min to prevent overheating and potential damage.
The DF300B is designed specifically for the Suzuki Dual Prop System
featuring contra-rotating propellers with a three-blade/three-blade
configuration. The recommended propeller selection ranges from 12 inches
to 31.5 inches pitch.
The propeller blade geometry has been optimized to work in this
configuration, resulting in incredible grip and acceleration across the
operating range. This design records high speeds even under heavy loads
and at high rotation speeds, with exceptional stability achieved because
each propeller rotates in a different direction, balancing the turning
forces.
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): 338 kg (744 lbs)
Engine Mounting: Rubber damper mounting 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.)
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)
Maintenance Features: The self-adjusting timing chain is
maintenance-free. The Suzuki Water Detecting System alerts the operator
with both visual and audio warnings when water is present in the fuel,
preventing issues like poor combustion, power loss, and corrosion. The
optional Troll Mode System allows precise trolling speed control
adjustable from 600 to 1200 r/min through the multi-function gauge. A
tool kit is provided with the outboard for basic maintenance tasks.
The Suzuki DF300B is engineered specifically for demanding applications
requiring exceptional torque and thrust, particularly for heavy boats
and commercial operations. Large Cruising Catamarans: The Aspen C128, a
44-foot cruising catamaran, is powered by twin Suzuki DF300B outboards,
demonstrating the engine's capability to efficiently drive substantial
vessels weighing up to 24,000 lbs. In sea trials, twin DF300Bs delivered
0-20 mph acceleration in 9.5 seconds, a top speed of 30.5 mph, and
remarkable single-engine range extending to 579 miles at 7.9 mph.
Heavy Sports Fishing Boats: Ideal for large center consoles and
sportfishing boats requiring powerful thrust for quick planing and
exceptional handling in offshore conditions. Commercial Applications:
Built for everyday use in commercial operations where reliability,
durability, and fuel efficiency are paramount for pushing heavy loads.
Large Pontoon and Deck Boats: Provides the torque necessary for
oversized pontoon boats and deck boats carrying substantial passenger
and gear loads.
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