Twelve years after starting the four-stroke revolution with its award winning DF60 and DF70 outboards, Suzuki has reinvented the category with two efficient models, the DF70 and DF90. As the first of Suzuki’s new generation four-strokes, they are a showcase of advancements and achievements—such as digital sequential electronic fuel injection, a powerful 2.59:1 final drive ratio, and a zero maintenance self-adjusting timing chain. They also feature Suzuki’s proven offset drive shaft which, used in combination with a newly designed powerhead, contributes to making the DF90 the smallest and lightest four stroke outboard in its class. This compact, lightweight design also makes any of these three outboards ideal for use on a wide range of boat types.
These outboards open up more options for boaters in search of the perfect combination of power and performance. Cowlings on both outboards feature bold graphics on their sides and Suzuki’s “S” logo on front giving this generation of four-strokes a sharp look.
The making of a compact outboard
Suzuki’s engineers are well known for their ability at reducing the size of the outboard. Their skills have created some of the most compact four-stroke outboards in their respective classes. Taking a fresh approach to the DF70/90, every part and component has been designed from the ground up. Applying the knowledge and technical advancements gained over the last decade, Suzuki engineers succeeded again at reducing outboard size and weight.
Pioneered with the first generation DF90, Suzuki’s offset driveshaft has played an effective role in reducing the size of the outboard. The design uses intermediate reduction gearing to position the crankshaft in front of the driveshaft, moving the outboard’s center of gravity forward for better weight distribution on the transom. It also provides improvements in power performance, balance, and vibration reduction. Combining the offset driveshaft with a redesigned powerhead, Suzuki engineers have created an outboard that is about 7.5cm (3 inches) shorter than the original DF90 and up to 23cm (9 inches) shorter than competitive models making this DF90 the most compact outboard in its class. Its compact design facilitates installation on a wider range of boats, and offers more room around the transom for fishing and other activities.
Suzuki Lean Burn Control System
The lean burn control system is designed to run on a thinner fuel mixture through the use of a lean air-fuel ratio. Suzuki engineers designed a system that predicts fuel needs according to operating conditions. It achieves added fuel economy through a reduction of pumping loss. In order to balance fuel efficiency with clean emissions, the system sets up air-fuel ratio taking advantage of the reaction characteristics of exhaust emissions. The system also has a wide lean burn range that extends up into the top speed range providing more efficient operation at cruising speed as well.
Mechanically Efficient Design
Looking beyond fuel systems for solutions, Suzuki engineers explored ways they could improve efficiency by reducing mechanical loss. They designed a new oil pump that delivers greater mechanical efficiency and improved hydrodynamics in the lubrication system, allowing oil to move through the system with less resistance. In reducing mechanical loss in these and other areas, Suzuki has created a more efficient engine that contributes to better fuel economy.
Multi-Point Sequential Electronic Fuel Injection
The first generation DF70 was awarded the National Marine Manufacturers Association’s Innovation Award for, among other firsts and advancements, its use of Suzuki’s Multi-Point Sequential Electronic Fuel Injection system. The second generation DF70/90 uses this sophisticated system once again to deliver instant throttle response, improved fuel economy, and low emissions. The system incorporates the ECM’s 32-bit computer, which gathers and processes vital operating data in real time from a series of sensors located in critical areas on the engine, to calculate the optimum amount of fuel and air to be injected at high pressure into the cylinders. The system offers excellent fuel efficiency and reduces emissions enabling these outboards to meet CARB 2008, one of the world’s strictest emissions regulations. Other benefits include smooth starts, and maximum operating efficiency.
DOHC 4-Valve Engine
The DF70/90 benefit from Suzuki’s unrivaled experience in the design and manufacture of motorcycle, automotive, and marine engines. Drawing upon their past advancements and achievements, Suzuki engineers have provided these new outboards with advanced engineering that delivers high power output, performance, fuel economy, and efficient operation. Starting with an in-line 4-cylinder block, Suzuki designed a more compact dual overhead cam (DOHC) powerhead with four valves per cylinder. This design has reduced the overall size of the outboard while providing high performance power. Power is delivered via a two-stage mixed cam drive system consisting of gears that transfer power between the crankshaft and the drive shaft, and a chain that delivers power from the drive shaft to the camshaft.
Two-Stage Gear Reduction
To take maximum advantage of the power produced by these high performance engines, Suzuki engineers have utilized a two-stage gear reduction ever since the introduction of the original DF90. The second generation DF70/90 follow in their predecessor’s footsteps employing the same method to provide an efficient means of supplying maximum propulsion. The key to gaining maximum propulsion is through the use of a large diameter propeller with a suitable pitch. But spinning a larger propeller requires more torque, which requires larger gears or a larger gearbox adding weight and resistance that do not always produce effective results. Suzuki engineers have long used a two-stage gear reduction system that provides the needed torque without adding unwanted bulk and weight. Through this method, the DF70/90 with a powerful 2.59:1 final drive ratio, produces the needed torque for quick acceleration and great top-end speed.
Streamlined Gear Case and Highly Efficient Propeller
The gear case on both the DF70/90 utilizes a hydrodynamic design that was first introduced on the flagship DF300. As the lower unit moves through the water its sleek form reduces drag by up to 36% compared to conventional designs, contributing to faster acceleration and increased speed.
Thanks to the robust torque delivered with Suzuki’s two-stage gear reduction, these outboards can turn a large diameter propeller. Suzuki engineered a new highly efficient propeller that takes advantage of this torque to provide faster acceleration and higher top speed.
High Output Alternator
Suzuki’s DF70/90 feature powerful 27A alternators that are designed to generate the bulk of their power at low rpm. These high-output alternators deliver 22A even at a low 1,000 rpm. In most situations, that’s enough power to keep an assortment of marine electronics and other accessories operating all day long.
Taking a fresh look at the gear case, our engineers redesigned the transmission and shifting system, utilizing new dimensions optimized for strength and rigidity. Components were engineered with greater precision and tighter tolerances to reduce play and noise. Incorporating a shift sensor into the system, the ECM now monitors shift action and then controls the ignition for precise shifting. Overall, refinements to the system led to a 40% reduction in shifting effort as compared to the original DF90, resulting in improved performance, precision control and shifting.
Suzuki Easy Start System
The Suzuki easy start system no longer requires the operator to hold the key until the engine starts. Now simply turn the key and release. The starter will stay engaged until the engine starts. The system also features more precise cylinder detection, fuel injection, and ignition control to deliver smoother and improved starts, more efficient combustion, and greater fuel economy making the outboard more environmentally friendly.
Dual Engine Flush Ports
The buildup of salt, sand, and dirt in the engine’s cooling system can lead to damage over time. The DF70/90 are designed with dual freshwater flush ports to make flushing of the cooling system as convenient as possible. One inlet located on the port side and a second on the front panel provide easy access and facilitate flushing of the system whether the boat is in or out of the water.
CARB Three-Star Label
The DF70/DF90 have received the CARB three-star rating which identifies engines that meet the California Air Resources Board’s 2008 exhaust emission standard one of the strictest exhaust regulations to date.
The DF70/90 are equipped with a timing chain that uses an automatic hydraulic tensioner to keep tension in check. The system provides users with years of maintenance free operation
New Trim and Tilt Limit System
The new trim and tilt limit system is designed to protect the boat from damage that can occur when tilting the outboard. The system is designed with a tilt angle sensor that incorporates both the functions of a tilt limit and trim sender. Using a step-free, continuous type tilt limiter makes installation of the outboard possible on nearly any type of boat.
Suzuki Anti Corrosion Finish
Suzuki’s specially formulated anti-corrosion finish increases the durability of the engine and helps to protect parts of the aluminum exterior that are constantly exposed to saltwater. Applied directly to the outboard's exterior, this advanced finish allows maximum bonding of the finish to the outboard’s aluminum surface, creating an effective treatment against corrosion.