Suzuki DF300AP Specifications
| Engine Model: Suzuki DF300AP |
| Engine Type: 4-stroke 6-cylinder DOHC 24-valve gasoline outboard engine |
| Total Displacement: 250 cu.in (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 DF300AP is a technologically supreme
outboard that redefines expectations for V6 marine power. Built around a
4.0-liter powerhead with a narrow 55-degree V-angle, it delivers its
rated 300 Hp with remarkable smoothness and refinement. The engine
incorporates Suzuki's Lean Burn Control System, which optimizes fuel
efficiency across the operating range, resulting in fuel savings of up
to 14 percent compared to the original non-Lean Burn DF300 without
sacrificing any power.
The world-first Selective Rotation system integrates both regular and
counter-rotation operation into a single lower unit, a revolutionary
advancement for twin-engine installations. With Suzuki Precision Control
electronic throttle and shift, Variable Valve Timing (VVT), and a host
of durability enhancements, the DF300AP delivers the ultimate
combination of power, efficiency, and sophisticated control.
Engine Model: Suzuki DF300AP
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 89.0 mm (3.86 in x 3.50 in)
Piston Displacement: 4028 cc (250 cu. in)
Maximum Output: 220.7 kW (300 Hp)
Full Throttle Operating Range: 5700-6300 rpm
Fuel Delivery System: Multi-Point Sequential Electronic Fuel Injection
with Lean Burn and Oxygen Sensor Feedback
Alternator: 12V 54A
Trim Method: Power Trim and Tilt
Gear Ratio: 2.08:1 (Two-stage Reduction Gear)
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: 15" - 27.5" pitch
Starting System: Electric
Ignition System: Fully-transistorized Solid State Direct Ignition
Engine Lubrication: Trochoid pump pressure lubrication
Engine Oil Capacity: 8.0 L (8.5/7.0 US/Imp. qt.)
Gearcase Oil Capacity: 1.1 L (1.2 US qt.)
Fuel Type: Automotive gasoline (94 research octane recommended)
Spark Plugs: NGK BKR6E
CARB Emissions Rating: 3-Star Ultra-Low
The DF300AP is built around a potent 4.0-liter V6 powerhead with a
narrow 55-degree bank angle, contributing to its remarkably compact
dimensions. The block is engineered for high performance and durability,
featuring strengthened components throughout. The powerhead incorporates
a DOHC 24-valve configuration for optimal airflow and combustion
efficiency.
A key innovation is the two-stage cam drive system, which first uses
gears to transfer power from the crankshaft to a driveshaft, and then a
self-adjusting, oil-bathed timing chain with an automatic hydraulic
tensioner to drive the camshafts. This design allows for a more compact
cylinder head and provides maintenance-free operation for the life of
the engine.
Suzuki's Variable Valve Timing (VVT) system, hydraulically controlled by
oil pressure, optimizes intake valve timing to maximize torque in the
low and mid-range. The system automatically adjusts valve timing by
altering intake camshaft timing, creating momentary overlap where both
intake and exhaust valves are open, resulting in optimum timing for low
and mid-range operation. This delivers the robust acceleration essential
for outboard applications.
The offset driveshaft design positions the powerhead forward of the
driveshaft, shifting the center of gravity for a more compact mounting
footprint and improved weight distribution on the boat's transom.
The DF300AP's fuel system is highly advanced, centered on the Suzuki
Lean Burn Control System. This technology uses an O2 sensor feedback
loop to predict fuel needs according to operating conditions, allowing
the engine to run on a more efficient, leaner air-fuel mixture from
low-speed operation through the cruising range. In-house testing
demonstrates that the DF300AP is 14 percent more economical than the
original non-Lean Burn DF300 without sacrificing any power output.
This system works seamlessly with the Multi-Point Sequential Electronic
Fuel Injection, which precisely meters fuel to each cylinder for optimal
combustion. The O2 Sensor Feedback Control System enables cleaner and
more stable emissions by controlling the air-fuel ratio across each of
the engine's operating ranges.
Additional fuel system enhancements include a fuel cooler that cools
fuel before it enters the engine, increasing fuel density for better
combustion and improved performance. An 81mm spherical bore throttle
body smoothes turbulent airflow during acceleration for increased
throttle control and stable engine operation at low rpm. The engine also
features a large air intake with a water separator to keep moisture out
of the electronic throttle body and a heat shield to prevent intake air
from being heated by the engine.
The DF300AP employs a trochoid pump pressure lubrication system to
ensure consistent and reliable pressurized oil delivery to all critical
engine components, including the crankshaft, connecting rods, and the
valve train with its VVT components. The engine has a substantial oil
capacity of 8.0 liters.
Cooling efficiency is enhanced by a dual water inlet system, a
significant feature of the DF300AP. By positioning one water intake at
the gearcase nose and a second lower intake, the system increases water
flow into the cooling passages, delivering greater cooling efficiency,
especially at high speeds and during operation in shallow water
conditions.
The forward inlet at the gearcase nose delivers a greater water supply
at high speeds, while the second lower inlet allows the engine to
operate effectively in shallow water. For post-operation maintenance,
the DF300AP is equipped with freshwater flushing ports, making it
convenient to flush salt, sand, and other debris from the cooling
system.
| Mid Section and Lower Unit |
The mid-section and lower unit of the DF300AP house its most
groundbreaking features. The newly designed low-drag gearcase was
developed specifically to accommodate the Suzuki Selective Rotation
system.
While the case itself is larger internally to accommodate more durable
components, it features a smoother, more hydrodynamic external shape
that moves through the water with less drag and greater efficiency.
The hallmark feature is Suzuki Selective Rotation, a world-first system
that integrates both regular and counter-rotation operation into a
single lower unit. By changing the gear-shift mode and adding a
counter-rotation propeller, the same outboard can operate in either
direction.
In counter-rotation mode, power is transmitted through the reverse gear,
which has been engineered with the same characteristics as the forward
gears. This is made possible through a special, unified design of gears,
shafts, and bearings, with redesigned gears using a different alloy and
larger diameters for superior rigidity and durability.
The lower unit utilizes an aggressive 2.08:1 final drive ratio, allowing
it to turn a large 406mm (16-inch) diameter propeller available in
various pitch sizes for optimum performance on a wide variety of boats.
Exhaust is channeled through the propeller hub for quieter operation.
The Power Trim and Tilt system provides hydraulic control over the
outboard's angle, enabling the operator to adjust the boat's trim for
optimal performance, fuel efficiency, and ride comfort. The system
includes tilt limit features to protect both the engine and boat from
damage.
The DF300AP is designed to work with a range of high-performance
stainless steel propellers to match various boat types and load
conditions. The recommended propeller pitch selection ranges from 15
inches to 27.5 inches.
The robust 2.08:1 gear ratio and the low-drag gearcase are engineered to
effectively transfer the engine's power to a large 16-inch diameter
propeller, optimizing thrust and overall performance. Available
propeller options include various pitch sizes from 15 through 27.5
inches, with counter-rotation propeller options also available for the
Selective Rotation system.
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): 274 kg (603 lbs)
Dry Weight (Extra-Extra Long Shaft - XX): 279 kg (614 lbs)
Engine Mounting: Shear Mount 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
Gearcase Oil Capacity: 1.1 L (1.2 US qt.)
Spark Plugs: NGK BKR6E. Spark Plugs: 25-29 Nm (18-21 lb-ft)
Spark Plug Gap: 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,
helping to prevent poor combustion, lower power output, and corrosion.
Freshwater flush ports simplify cooling system cleaning. An optional
Troll Mode system allows for precise trolling speed control.
Offshore Sports Fishing Boats: Its power, durability, and advanced
features like Selective Rotation for twin installations make it ideal
for offshore center consoles and sportfishing boats in the 24 to 30-foot
range. High-Performance Cruisers: Provides the muscle needed for
powering express cruisers, cabin cruisers, and other large trailerable
boats.
Saltwater Use: The engine is extensively protected by Suzuki's
comprehensive Anti-Corrosion Finish, which includes multiple layers of
protection applied to aluminum surfaces using high-strength bonding.
Features like dual water inlets and freshwater flush ports make it
exceptionally well-suited for long-term durability in harsh saltwater
environments. The engine meets CARB 3-Star Ultra-Low emissions standards
and conforms to the Recreational Craft Directive.
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