DF175AP / DF150AP

Big Block—High Performance Engine

The new DF175AP/150AP development team based both of these new Suzuki outboards on a big block inline four-cylinder four-stroke engine with a 2,867cm³ displacement. The block is topped with a DOHC powerhead that provides four-valves per cylinder for high performance. While the large displacement allows both to deliver exceptional acceleration and velocity, our engineers made sure that the outboard's final dimensions are as compact and lightweight as possible.
Both outboards feature some of the best of Suzuki's advanced technologies that have been developed to extend engine performance.

High 10.2:1 Compression Ratio and Largest in Class Displacement^*2

Compression and displacement each play important roles in delivering performance and power output. Displacement has a direct effect on acceleration and torque so a bigger displacement is generally going to deliver more of both. Higher compression ratios allow the engine to get more output out of the combustion process resulting in noticeable improvements in performance and power. Drawing on our extensive motorsports experience and expertise in building race engines, Suzuki engineers have combined a 2,867cm³ displacement (the largest in each outboard's class) with a high compression ratio of 10.2:1 to obtain great performance from these compact engines.

*2:as of Aug, 2016.

Suzuki Selective Rotation

Large boats equipped with multi-outboard installations generally pair a standard rotation outboard with a counter-rotation model to keep the boat traveling in a straight line and on an even keel. Once requiring the purchase of a dedicated counter-rotation model, Suzuki's innovative Suzuki Selective Rotation eliminates that need by incorporating a special, unified design of gears, shaft, and bearings in the lower unit that allow the outboard to operate reliably and efficiently in either direction. Available on both the DF175AP and DF150AP, counter-rotation operation requires an optional activation switch that connects to a circuit inside of the engine compartment plus the installation of a counter-rotation propeller^*1.

*1:Consult with your dealer before changing Standard Rotation to Counter-Rotation (or vice versa).
The optional connector and additional propeller are needed to change the outboards rotation.

Semi-Direct Air Intake System

Underneath the modern upswept engine cover are a number of function-focused features that enhance engine performance. Both the DF175AP and DF150AP are equipped with a Semi-Direct Air Intake system that brings cooler air directly into the multi-stage induction module. Engines that breathe cooler air can operate more efficiently resulting in greater acceleration and top-end speed.Covers also have ports on the top that allow the rotating flywheel to push warm air inside of the cover to the outside helping to reduce temperature inside of the cover.

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 throttle and shift operation with minimal friction, the system's computer is processing and transmitting commands in real-time to actuators at the engine that deliver precise throttle control 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 flow 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 offers precision control for single, twin, triple or quad installations as well as dual station operation.

Suzuki Lean Burn Control System

The Suzuki Lean Burn Control System is an intelligent fuel delivery system that achieves remarkable improvements in fuel consumption making fuel-efficient four-stroke outboards even more economical. Monitoring engine performance and operating conditions in real time, the system uses the 32-bit onboard ECM to predict fuel needs and deliver a leaner, more precise fuel mixture across the outboard's operating range. The results show significant improvements in fuel economy across the entire powerband, including the cruising range where the engine is used a majority of the time.

Counter Balancer System

One of the inherent characteristics common to in-line four-cylinder engines when operating at high rpm is a secondary vibration that is directionally in line with the piston's movements. To neutralize this vibration, Suzuki engineers utilize a secondary balancer system that counters the piston's movement with a horizontal motion. To achieve this, the balancer is divided into left and right sections each rotating in an opposite direction at twice the speed of the crankshaft, effectively countering the secondary vibrations and producing smoother engine operation.

O₂ Sensor Feedback Control System

A key sensor in the electronic fuel injection system, the O₂ Sensor Feedback Control system provides accurate, real-time information that the ECU uses to manage the fuel/air ratio as operating conditions change. Utilized on many of Suzuki's high-end outboards, the O₂ Sensor Feedback Control system helps maintain optimum engine operating efficiency across the engine's full operating range.

Resonator

The engine's exhaust system is a well-known source of engine noise, but another, often overlooked source is the intake manifold. Air being sucked into the intake manifold at high velocities can generate a harsh sound. The DF175AP/DF150AP incorporate an air intake resonator that reduces such noise keeping operation exceptionally quiet.

Knock Sensor

The knock sensor monitors combustion to provide the ECM with information needed for precise management of engine timing for optimum performance. In addition to maximizing power output, the system also helps increase engine durability.

Thrust Mount System

Both the DF175AP and DF150AP incorporate a combination of soft type and high thrust rubber mounts on both upper and lower mounts to reduce engine vibration and provide stable operation. Soft type rubber mounts are used to absorb vibrations generated in the idling through 2,000 rpm range while high thrust rubber mounts deliver stable operation under high loads increasing power and performance.

Variable Valve Timing (VVT)

Variable Valve Timing is utilized on many of Suzuki's high-end outboards to deliver high performance across the outboard's full powerband while retaining the benefits that four-stroke technology provides. The system starts with an innovative cam profile designed for delivering maximum output and performance at high rpm. Variable Valve Timing is used to vary intake timing with the camshaft to optimize timing for low to mid-range operation. This allows the engine to deliver maximum power output across its entire operating range producing greater low to mid-range torque for powerful acceleration. The entire process happens automatically leaving you to enjoy the power and performance.

Quiet Operation

Suzuki four-stroke outboards have long been noted for their exceptionally quiet operation. Suzuki engineers go to great lengths incorporating methods designed to keep outboard operation as quiet as possible.

Multi-Stage Induction (MSI)

Getting the right amount of air into the cylinder has a great impact on performance. High-speed operation typically requires a greater volume of air, low-speed less. Suzuki's Multi-Stage Induction system meets these needs by utilizing two intake manifold pipes per cylinder to ensure the engine gets the right amount of air. At low rpm, air enters the combustion chamber through a longer, curved manifold pipe designed to improve combustion and boost low-end torque. As rpm increases, the valves open on the direct intake pipes. Shorter and lacking resistance, these pipes allow a greater volume of air into the chamber, increasing the engine's ability to breathe efficiently at high rpm resulting in higher power output during high-speed operation.

Offset Drive Shaft

Pioneered by Suzuki, the use of the offset drive shaft on four-stroke outboards has long been utilized to reduce the size of the outboard. Found on all Suzuki four-strokes from the DF70A and up, this design positions the crankshaft in front of the drive shaft simultaneously moving the outboard's center of gravity forward. While the design contributes greatly to the outboard's overall compactness and increased power performance, it also moves the engine's axis of inertia, the point where engine vibrations are at a minimum, up over the upper engine mount, thus greatly reducing vibration. These outboards also incorporate two-stage gear reduction designed to take maximum advantage of the power produced by these high performance engines. Providing a final drive ratio of 2.50:1—the largest you can find in either of these outboard classes—it delivers powerful torque for quick acceleration and great top-end speed.

32-Bit ECM (Engine Control Module)

Both the DF175AP and DF150AP utilize a 32-bit ECM (Engine Control Module) that provides precision control over motor operation, particularly the ignition and fuel delivery systems. This powerful onboard computer monitors and processes key data gathered in real-time from a series of sensors placed in areas crucial to engine operation. Those sensors include the Manifold Absolute Pressure Sensor, Crankshaft Position Sensor, Intake Air Temperature Sensor, Shift Position Sensor, Throttle Position Sensor, Cylinder Wall Temperature Sensor, Camshaft Position Sensor, and Exhaust Manifold Temperature Sensor. Using these data the computer delivers precision control of the engine's ignition and fuel systems maintaining an optimal spark and fuel supply under all operating conditions.

High Output Alternators

Today's boats are equipped with a wide array of electronics that demand an ample flow of power to keep them running. With that in mind, Suzuki engineers have equipped the DF175AP and DF150AP with an alternator that produces a majority of its maximum 44A (12V) output with the motor running at a low 1,000 rpm—enough power for most circumstances.

Multi-Point Sequential Electronic Fuel Injection

Suzuki pioneered the use of electronic fuel injection in four-stroke outboards with the launch of its original DF70/60 in 1997. Suzuki's Multi-Point Sequential Electronic Fuel Injection supplies each of the engine's cylinders with an optimized mixture of fuel and air that is injected into the cylinder at high pressure according to commands from the ECM's 32-bit computer. The system delivers improved fuel economy, crisp acceleration and reduced emissions that meet emissions regulations. It also conforms to the Recreational Craft Directive (RCD) Standards, Directive 2003/44EC of the European Parliament and of the Council, and has received a three-star rating from the California Air Resource Board (CARB).

Suzuki Keyless Start System^*3

Suzuki's Keyless Start system utilizes a proximity key-fob that transmits an access code to the engine's starting system. As long as you have the key-fob on your person, all you need to do is stand within one meter of the console, connect the emergency switch cord, turn on the main switch then start the outboard with a push of a button. With the key remaining safely in your pocket, the system offers simple, stress-free operation while reducing the risk of a lost key. The system also makes for an excellent theft deterrent since the outboard will not start without the proper access code. The key-fob also floats so should it ever go overboard you can retrieve it.

*3:Availability may differ in some regions. Please contact your local Suzuki dealer for more information.

Water-cooled Voltage Regulator with Isolator

Water-cooled voltage regulators incorporated on both outboards dissipate heat in the regulator to enhance durability. The battery charging system also incorporates an isolator function that allows the use of two batteries. The system splits electric current into two circuits and is designed to safeguard the main battery in the event that the sub battery becomes drained.

Fuse Box

Fuses for the outboard's electrical system are housed in a single fuse box located on the side of the outboard motor. This design keeps the outboard's exterior clean while providing convenient access.

Tilt Limit System

To protect the boat and motor from damage that can occur when tilting the motor, both outboards incorporate a user adjustable tilt limit switch that prevents the outboard from tilting beyond a predetermined point.

Dual Engine Flush Ports

Over time, salt, sand, and dirt buildup can restrict flow in the cooling system causing damage. To help prevent such buildup, both outboards are equipped with two freshwater flush ports that make flushing the cooling system as easy as possible. With one port located on the port side of the down housing and a second on the front panel, you'll always have easy access to the flushing system whether the boat is in or out of the water.

Suzuki Water Detecting System

Water in the fuel can lead to problems that include poor combustion, lower power output, and corrosion. The Suzuki Water Detecting System is designed to help protect the engine from moisture in the fuel utilizing a water detecting fuel filter to alert the operator with both visual and audio warnings when water is present in the fuel. The filter is also designed to let you check for water visually.

Suzuki's Anti-Corrosion Finish

To guard against corrosion, Suzuki protects its outboards with its own specially formulated Suzuki Anti-Corrosion Finish. Applied directly to the outboard's aluminum alloy, this finish provides maximum bonding of the finish to the aluminum surface. Layering an epoxy primer undercoat, black metallic (or white) finish, and clear acrylic fiber finish on top of this forms an effective treatment against corrosion, protecting those parts of the outboard's aluminum alloy that are constantly exposed to saltwater.