August 01, 2012
By Sam Hudson
The new Suzuki DF300A mixes technology and innovation. Rated at 220.7kW, the 4.0-liter, DOHC V6 24-valve ?agship DF300A delivers plenty of power and torque. Highlights are below:
New Lower Unit
Compared to the original DF300, the biggest changes you'll ?nd on these outboards are in the lower unit, which was redesigned for the Suzuki Selective Rotation system—the world's ?rst integration of regular and counter-rotation models into a single unit. The system consists of a new drive gear layout in the lower unit that allows the outboard to operate in either regular or counter-rotation mode, and a switch that connects to a circuit in the engine compartment that engages the counter-rotation mode.
Like the DF300, the new DF300A (also called the DF300AP) utilizes an aggressive ?nal drive ratio of 2.08:1 allowing it to turn a 406mm (16-inch) diameter propeller available in various pitch size for optimum performance on a wide variety of boats.
Suzuki Selective Rotation
In multi-outboard installations on large boats, a counterrotation outboard is usually paired with a regular rotation model to help keep the boat traveling on an even keel and in a straight line. The DF300AP is built with special counter rotating gearing in the lower unit, which causes the prop to rotate in the opposite direction. Suzuki Selective Rotation eliminates the need to purchase a dedicated counter-rotation outboard by using a special switch that when connected to a circuit inside of the engine compartment, turns a regular rotation outboard into a counter-rotation model with a counter rotational propeller. This industry ?rst is made possible through a special, uni?ed design of gears, shaft, and bearings in the lower unit that are designed to operate reliably and e?ciently in either regular or counter-rotation directions.
Suzuki's Precision Control
Suzuki Precision Control is a technologically advanced computer-based control system that replaces the mechanical control cables found in conventional control systems with electronic wiring that eliminates
the source of friction and resistance. While you enjoy smooth, little friction throttle and shift operation, the system's computer is processing and transmitting commands in real-time to actuators at the engine that deliver precise throttle controls with smoother, decisive shifting. This is most evident in the low rpm range where operation is noticeably smooth and accurate. When combined with Suzuki's Lean Burn Control System it allows control of fuel and air ?ow to boost the limit of the controllable revolution range improving fuel economy over a wide operating range. Suzuki Precision Control also features built-in systems that help guard the engine and drive against damage due to mishandling, and its design and simple wiring make installation easy, reducing the time required for rigging and adjustment. The system o?ers precision control for single, twin or triple installation as well as dual station operation.
Suzuki's Lean Burn Control system
Suzuki's innovative Lean Burn Control System was ?rst introduced on the DF90A/80A/70A to great acclaim from boaters and the media alike. It predicts fuel needs according to operating conditions allowing the engine to run on a more e?cient fuel mixture through the use of a lean air-fuel ratio. It delivers its bene?ts over a wide operating range, providing signi?cant improvements in fuel economy from low-speed operation into the cruising range. Combining this system with the Suzuki Precision Control, electronic throttle and shift system, allows the operator precisely control to increase or decrease the engine RPM for improved fuel economy over a wider operation range. This combination also delivers smooth power transitions throughout the entire RPM range. In-house testing shows that while cruising, the DF300A is 14% more economical than the original non-Lean Burn DF300 without sacri?cing any power.
O2 Sensor Feedback Control System
Both the DF300A are equipped with an O2 Sensor Feedback Control system that enables emissions to be cleaner and more stable. The system controls the air to fuel ratio across each of the engine's operating ranges providing an optimum amount of fuel to the engine regardless of rpm.
