Suzuki DF250SS User manual

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The DF250SS represents a new kind of Suzuki outboard—a “Sport 4-Stroke” designed for the
sportsman who is serious about outboard performance. Based on a 4.0-liter Big Block V6 the DF250SS
produces 250 horsepower and delivers outstanding acceleration throughout the entire powerband
thanks to the incorporation of some of Suzuki’s most advanced technologies. With a 20-inch transom, it’s
perfect for bass boats, sport pontoons, ski boats, flats and bay boats or any other boat that demands
power, performance and reliability. The DF250SS also offers all the advantages of Suzuki’s 4-stroke
technology, such as superior fuel economy, quiet, low vibration, and environmentally friendly operation,
all while providing impressive performance and rock solid reliability.
Suzuki 250SS
Ifyou’re as serious about outboard performance as you are about your sport, then the
DF250SS is definitely for you.

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DF250SS PRODUCT INFORMATION

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DF250SS Main Features S
■The DF250SS is designed to deliver performance and reliability that today’s sport users
demand.
■4.0-liter Big Block V-6 engine–combined with Suzuki’s Variable ValveTiming (VVT) and Multi
Stage Induction delivers superior acceleration throughout the entire powerband.
■The 20-inch transom is perfect for bass boats, sport pontoon boats, ski boats, flats and bay
boats or any boat that is designed for the sportsman who is serious about outboard
performance.
■Gear case features a hydrodynamic design, introduced first on the flagship DF300, that
reduces drag resistance for fast acceleration and increased top speed.
■The DF250SS complies with the California Air Resources Board's (CARB) 2008 exhaust
emission standard and has earned the 3-Star Ultra Low Emission Rating.

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Diagram of VVT Mechanism
DSuzuki Technologies Deliver Outstanding Performance
Camshaft Position Sensor
Rotation Direction
VVT Actuator
Throttle Opening Angle
Water Temp
Feed
back
Cam Position
Crank
Position
Manifold Pressure
Water Temp Sensor
Throttle Sensor
Map Sensor*
Intk Camshaft Ex Camshaft
Crankshaft Position Sensor
Duty Control
Crankshaft
ECM
Target
Advance
Actual Valve
Timing
Intk Camshaft
Retard
Advance
Drain
Oil
Filter
Oil
Pump
Oil Pan
Engine Oil Flow
Oil Control Valve(OCV)
Signal
*Manifold Absolute Pressure Sensor
DF250SS PRODUCT INFORMATION
TORQUE
LOW MID
ENGINE SPEED
HIGH
without VVT
with VVT
ValveOverlap
Valve Lift
Ex Valve
Advance
40°Movable Angle
Intk Valve
Retard
Crank Angle
VVT (Variable Valve Timing)
Suzuki engineers started o in a big way by designing the
DF250SS based on a big block4.0-liter engine, the largest displace-
ment found inthis class. is V6 engine features an aggressive cam
prole, delivering maximum output and performance at high rpm,
and Suzuki’s advanced Variable Valve Timing (VVT), provides the
DF250SS with the torque neededto boostlow- to mid-range
acceleration. VVT provides this boost by adjusting theintake valve
timing, allowing intake valves to open before the exhaust valves are
fullyclosed. is process creates a momentary overlapin the
timing where bothsets of valves are open. WithVVT,this overlap
can be increased or
decreasedby altering
intake timing with the
camshas to optimize
timing forlow- and
mid-rangeoperation.
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Alumite coating
Piston Resin coating
TORQUE (50N•m)
LOW MID
ENGINE SPEED (rpm)
HIGH
without Multi-Stage Induction
with Multi-Stage Induction
Torque Curve
Multi-Stage Induction Module
Air Flow in Multi-Stage Induction Module
Lower rpm High rpm
Close Open
Forged Pistons
eupper portion of each piston usedin the DF250SS is treated
with an alumite coating thatincreases heatresistance.A resin
coating appliedto the piston skirt improves resistance to wear and
reduces friction.
Fuel Cooler
ecooler the fuel the denser it is, and the denser it is, the
more performance it delivers. e DF250SS incorporates a water -
cooled fuel railin the fuel delivery system. e fuel is cooled before
it is injectedinto the cylinder resultingin better combustion and
better performance.
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Multi-StageInduction
Suzuki engineers also utilized Suzuki’s Multi-Stage Induction,
which changes intake manifold pipelength according to engine rpm
to enhance engine performance.e DF250SS utilizes two intake
manifold pipes per cylinder;one operates at low engine rpmand
the other takes over at higher rpm. During low engine rpm, air
enters thecombustion chamber through the longer, curved mani-
fold pipe. e particular length of this pipe allows just the right
amount of fresh air intothe chamber to improvecombustion and
boostlow-end torque.
Asengine rpmincreases, a valve on theintake manifold opens,
letting air enter directly
into the combustion
chamber through the
short, straightintake pipe.
is allows a greater
volume of air intothe
chamber,increasing the
engine’sability to breathe
at high rpm, thus
improving high-end
power output.
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Offset Drive Shaft
A
Offset Driveshaft
Suzuki incorporates a number of innovative designs into its
outboards. As a result, Suzukioerssome of the most compact
outboards in their class. One such design innovation is theoset
drivesha.
Positioning the crankshain front of thedrivesha, the
outboard’s center of gravity is moved forward. is contributes to
the overall compact size and provides improvedpower and
performance. It alsogreatly reduces engine vibrationsince the
engine’saxis of inertia, the point where vibrationsare at a
minimum, is in line with the upper engine mounts.
Streamlined Gear Case
eDF250SS takes advantageof the streamlined gearcase
introduced on the DF300 to reduce drag createdas the lower unit
moves through the water. is contributes to faster acceleration
and increasedspeed.
Suzuki’s Advanced Engineering Delivers Compact Designs
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Two-Stage Cam Drive System
eDF250SS incorporates Suzuki’s proven two-stage cam drive
system thatuses bothgearsand chain. e rst stage gears transfer
power between the cranksha and the drivesha. While the
second stage transfers power fromthe drivesha to thecam shas
with a chain. is system allows useof smaller diameter cam
sprockets, which in turn allow forareduction in valve angles also
reducing thesize of
the cylinder head.
Additionally, the
timing chain system
incorporates an
automatic hydraulic
tensioner to keep the
chain properly
adjustedand provide
yearsof
maintenance-free
operation.
DF250SS PRODUCT INFORMATION

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Suzuki’s Anti-Corrosion Finish
eoutside of theDF250SS is coveredwith Suzuki’s multi-
layered anti-corrosion nishthat is speciallyformulated to increase
the durability of theengine and help protectthe aluminum exterior
that is constantlyexposedto saltwater. is advanced nishoers
maximumbondingof the nish to theoutboard’s aluminum
surface, creating an eectivetreatment againstcorrosion.
Acrylic Resin Clear Topcoat
Acrylic Resin Black
Metallic Basecoat
Epoxy Primer
Undercoat
Suzuki Anti-
Corrosion Finish
Suzuki Aluminum Alloy
Flywheel Magneto
Fuel Filter with WaterSeparator
efuel system incorporates a large, easy to maintain fuel lter
that removes contaminants fromthe fuel before theycan reach the
engine. A water separator builtinto the fuel lter oers a height-
ened levelof protection by keeping water out of theengine.
Fuel Filter
Guarding Against the Elements S
LargeAir Intake, and Flywheelwith
Fan Blades
Increasingairow intothe engine canincrease power output, so
Suzuki engineers designed the DF250SS with dualair induction
ports to maximize airow intothe
engine to obtain maximum power
output. e increased airow delivers
more low- to mid-rangetorque and
provides the outboard witha wider
powerband.
eywheel is designed with fan
blades thatexpel heatfrom within the
engine cover and dischargethe hot air
out of theside of thecowl,keeping the
temperaturewithin the cowl under control.
R
Air Intake
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Plug Top
Ignition Coil
Direct Ignition System
Supplyingsparkto the DF250SS is an advanced ignition system
that utilizes integral type spark plug caps withbuilt-in ignition
coils. e system is controlledby the outboard’spowerful32-bit
computer and provides each cylinder withoptimum spark timing.
In addition to reducing thenumber of
parts and simplifying thewiring
system, this arrangement greatly
reduces electronic engine “noise”that
can interfere with VHF radios, sh
nders, and other marine electronics.
DF250S PRODUCT
GSuzuki’s Advanced Electronics Optimize Performance
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Regulator with Dual Circuit Charging System
eDF250SS features a built in dualcircuit charging system
that can be adapted* for use withdual-battery congurations.
When usedin this conguration, the system charges bothmain and
auxiliary batteries simultaneouslyon independent circuits. With
this design, youcan drain downthe accessory battery powering
your electronics and still haveafully chargedmain battery for
startingthe motor.
*Requires purchaseof optional wiring harness.
SINGLE CHARGING SYSTEM
DUAL CHARGING SYSTEM
High Output Alternator
eDF250SS generates electricityfrom a high outputalternator
that delivers 54A (12V) of electrical power. Suzuki’s design allows
the alternatorto produce a majority of its output at low rpm, so
even when operating at 1000rpm it canproduce approximately
38A of power.In most situations, this is enough power to keep an
assortment of electronics up andrunning.
0
5
10
15
20
25
30
35
40
45
50
55
1000 2000 3000 4000 5000 (rpm)
(A)
Magneto
Regulator
Regulator
Fuse Box
Main
Battery
Engine
Load
Magneto
Regulator
Regulator
Fuse Box
Auxiliary
Battery
Main
Battery
Engine
Load
DF250S PRODUCT INFORMATION
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32-Bit ECM and Suzuki’s Multi Point Sequen-
tial Electronic Fuel Injection
Suzuki pioneered the use of multi point sequential electronic
fuel injectionin four-strokeoutboards with the introduction of the
DF60 and DF70–therst four-strokeoutboards designed with
multi pointsequential electronic fuel injection. At the heartof the
DF250SS is a multi point sequential fuel injectionsystem which is
operatedby an ECM (Engine Control Module) using a series of
engine sensors to constantlymonitor crucialdata, in real time.is
comprehensive network of sensors includes the Manifold Absolute
Pressure Sensor, CrankshaPositionSensor, Intake Air Tempera-
ture Sensor, Cylinder Wall TemperatureSensor, CamshaPosition
Sensor, and Exhaust Jacket Temp eratureSensor. Using a powerful
32-bit computer, theECM processes datafrom all of these sensors
and instantly calculates the optimum amount of fuel to be injected
at high pressure into each cylinder.
Benets of this system include reduced
exhaust emissions, which allow the
DF250SS to comply withCARB 3-Star
emission requirements, lower fuel
consumption, smoother starts, crisper
acceleration, impressive performance,
and maximum eciency.

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Tilt Limit Switch
eoutboard tiltsystem
incorporates an adjustable tiltlimit
switch, which prevents the motor
from tiltingbeyond a predetermined
position. is canbe used to protect
both the boatand motor from
damage thatcan occur when tilting
the motor.
Dual Engine Flush Ports
ebuildup of sand and saltin the engine’scooling system can
lead to engine damage. To aid in reducing such buildup, the
DF250SS is designed withtwo freshwater ushports that make
ushing of the cooling system as convenient and easy as possible.
With one portlocated on therear paneland the second on the
frontpanel, access is easy and ushingout the system is possible
whether the boatis in the water or on thetrailer.
Features that Offer Convenient Operation
Tilt Limit System
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