DF150AP

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.

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 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.

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.

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.

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.

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 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.

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.

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.

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).

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.

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.