Big Block – High Performance Engine
Suzuki’s DF150 and DF175 are based
on an all-new inline four-cylinder DOHC
powerhead with a 2,867cm3 (174.9 cu.in.)
displacement—the largest to date in the
four-stroke, four-cylinder category.
While the added displacement contrib-
utes greatly to exceptional acceleration
and velocity, it doesn’t mean that these
engines are comparatively larger and
heavier in size. To the contrary, Suzuki’s
engineers have targeted these big block
motors to be the lightest four-strokes of
their kind.
Taking advantage of advances Suzuki
engineers have made in four-stroke
engine performance, the DF175 utilizes a
continuously variable valve timing system
much like that found in our flagship
DF250. Both the DF150 and DF175
share other advanced features including
multi-stage induction and a 32-bit
onboard computer that monitors and
controls engine functions. Both outboards
have also gained the CARB Three-Star
rating, which identifies engines that meet
the California Air Resources Board’s
2008 exhaust emissions standards.
2
Torque Curve
■ Advanced Technology for the
Performance
with VVT
Largest Displacement in Their Class
The new DF150 and DF175 utilize an all-new inline four-
cylinder four-stroke engine with a DOHC four-valve powerhead
that produces 150hp (110kW) and 175hp (129kW) respectively.
At 2,867cm3 (174.9 cu.in.), these two outboards offer the largest
displacement in the four-stroke, four-cylinder category to date.
And thanks to Suzuki’s innovative engineering, they are the
lightest in their category to date.
without VVT
VVT (Variable Valve Timing) (DF175)
In designing the DF175, our goal was to expand the potential of
the four-stroke engine and create an outboard that delivers high
performance along with the benefits of four-stroke technology.
Like the flagship DF250, the DF175 is designed with an
LOW
MID
HIGH
ENGINE SPEED
* At the comparison test, Multi-Stage Induction System of the
motor was operated.
aggressive cam profile and paired with Suzuki’s advanced Variable
Valve Timing (VVT) to increase the low to mid-range torque
outboards need when accelerating. The intake valve actually starts
to open before the exhaust valve fully closes, creating a momen-
tary overlap in the timing where both valves are open. Using
Variable Valve Timing, this overlap can be increased or decreased
by altering intake timing with the camshaft, thereby optimizing
camshaft timing for low and mid-range operation.
Air Flow in Multi-Stage Induction Module
Lower rpm
High rpm
Multi-Stage Induction (MSI)
The DF150 and DF175 incorporate a multi-stage induction
system to enhance engine performance by changing the length of
intake manifold pipes according to engine speed. The system
utilizes two intake manifold pipes per cylinder, one for operating
at low engine speed and another for operating at high. At lower
rpm, air enters the combustion chamber through the longer mani-
fold pipe, which is designed to deliver an optimum volume of
fresh air into the chamber to improve combustion and boost low-
end torque.
Torque Curve
As the engine speed surpasses a preset threshold, the valve on
the direct intake pipe opens up, letting air enter instantly into the
combustion chamber. Shorter and lacking resistance, this pipe gets
a greater volume of air into the chamber, increasing the engine’s
ability to breathe at high rpm, thus improving high speed power
output.
Torque
(with Multi-Stage Induction)
Torque
(without Multi-Stage Induction)
Suzuki engineers have equipped these outboards with many
other advanced features that contribute to engine performance.
A spherical bore throttle body produces smoother airflow
during acceleration. This results in greater engine control and
stable operation at low rpm.
LOW
MID
HIGH
ENGINE SPEED
3
■ Smooth Operation
Counter Balancer System
■ Durability and Reliability
Suzuki’s Anti-Corrosion Finish
In-line four-cylinder engines operating at high RPMs
generate a secondary vibration that is directionally in line with
the pistons’ movement. In order to counter this vibration, Suzuki
engineers utilize a secondary balancer system, which produces a
horizontal motion against pistons’ movement. To produce this
horizontal motion, the balancer is divided into left and right
sections, each rotating in an opposite direction. Rotating at twice
the speed of the crankshaft, the balancers effectively counter
these secondary vibrations and produce a smoother operating
engine.
Suzuki’s anti-corrosion finish is specially formulated
to increase the durability of the engine and protect those
parts of the aluminum exterior that are constantly exposed
to saltwater. Applied directly to the outboard’s aluminum
alloy, this advanced finish provides maximum bonding of
the outboard’s finish to its aluminum surface. Layered on
top is an epoxy primer
Acrylic Resin Clear Topcoat
undercoat, black
metallic finish, and
Acrylic Resin Black
Metallic Basecoat
clear acrylic fiber
Epoxy Primer
Undercoat
finish that together
form an effective
treatment against
corrosion.
Thrust Mount System
Suzuki Anti-
Corrosion Finish
In order to reduce vibration and provide stable operation,
the DF150 and DF175 use a combination of two different
rubber mount types. On both the upper and lower mounts, a
combination of soft type and high thrust rubber mounts are
utilized. The soft rubber mounts used in this configuration
are designed to absorb vibrations produced in the idling
through 2,000 rpm operating range. While adding to the
compact design and providing an improvement in power and
performance, this system also places the high thrust rubber
mounts in the best position to provide stable operation under
high loads.
Suzuki Aluminum Alloy
Enhanced Air Intake System
Maximizing airflow into the engine is one way to gain
maximum power output. The DF150 and DF175 are designed
with a large air induction port to increase airflow into the
engine. Air is channeled into a large silencer, then through
the intake manifold, and finally into the cylinders via a high
performance DOHC four-valve-per-cylinder head. The
increased airflow results in more low- to mid-range torque
and provides a wide powerband that is a must in an outboard
engine. The system also includes a water separator which
keeps water out of the air intake system.
Offset Drive Shaft
Suzuki’s offset drive shaft has proven successful in
reduction of size for the DF90, DF115, DF140, DF200,
DF225, and DF250. The DF150 and DF175 benefit from this
same design, which positions the crankshaft in front of the
drive shaft, simultaneously moving the outboard’s center of
gravity forward. While adding to the compactness of the
outboard and providing an improvement in power
performance, this system also places the engine’s axis of
inertia, the point where vibrations produced by the engine are
at a minimum, up over the upper engine mount thus, greatly
reducing vibration.
Offset Drive Shaft
Quietness
The DF150 and DF175
Comparison
are powerful outboards, but
powerful doesn’t mean that
100
Brand A (2st D/I 175PS)
they are noisy. Quiet opera-
tion has long been an
90
integral part of Suzuki four-
stroke outboard design.
80
DF175
A comparison of engine
operating noise levels
70
between the four-stroke
DF175 and its two-stroke
60
direct fuel injection (D/I)
counterpart is shown in the
50
LOW
MID
HIGH
graph. In this comparison it
is clear that the DF175
delivers quieter operation
rpm
*According to Suzuki Internal Running Test
over its entire range than its two-stroke counterpart.
4
■ Advanced Electronics
32-Bit ECM (Engine Control Module)
Multi-Point Sequential Electronic Fuel
injection
The ECM (Engine Control Module) allows much more
accurate control over the motor’s operation, particularly
the engine’s ignition and fuel delivery systems. The DF150
and DF175 rely on a powerful 32-bit computer in the ECM
to monitor and process crucial data, in real time, from a
series of sensors placed in critical areas on the engine. This
comprehensive network of sensors includes 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 Jacket
Temperature Sensor. Processing this data in real time, the
computer controls the engine’s ignition system and pro-
vides an ideal fuel supply under all operating conditions.
As Suzuki was the first outboard motor manufacturer
to incorporate multi-point sequential fuel injection in a
four-stroke outboard, it is only natural that the DF150
and DF175 would utilize the same. The system injects
the optimum amount of fuel at high pressure into each
cylinder according to commands from the ECM’s 32-bit
computer. Along with saving fuel, the system enables the
DF150 and DF175 to meet the world’s strictest emissions
regulations—CARB 2008—and pass the EPA’s 2006
regulations. Other benefits include quick starts, crisp
acceleration, smooth performance, and maximum effi-
ciency.
Multi Point Sequential Electronic Fuel Injection
Fuel Tank
Low Pressure Fuel Filter
Squeeze Pump
Low Pressure Fuel Pump
High
Pressure
Fuel Filter
Float
Vapor
Separator
Battery
Flywheel
Magneto
Crankshaft Position
Sensor (CKP Sensor)
Shift Position Sensor
High Pressure
Fuel Pump
Oil Control Valve (OCV)
ECM
Evaporation Hose
Ignition Coil
Fuel Cooler
Injector
Pressure Regulator
Camshaft Position
Sensor (CMP Sensor)
Neutral Switch
Intake Manifold
Vacuum Switching
Valve (VSV)
Starter Relay
Cylinder Head
Idle Air Control
Valve (IAC Valve)
Cylinder Block
Ignition
IG Switch
Throttle Body
Main Relay
OFF
Silencer
ST
Exhaust Jacket
Temp Sensor
Spark Plug
Fuse
Oxygen Sensor (Service tool only)
Cylinder Wall Temp Sensor
Intake Air Temp Sensor
(IAT Sensor)
Pilot Air
Adjust Screw
Manifold Absolute Pressure Sensor
(MAP Sensor)
Throttle Position Sensor
5
High Output Alternators
Two Engine Flush Ports
The DF150 and DF175 are equipped with alternators
that produce a maximum output of 44A (12V) and are
capable of producing
Salt, sand, and dirt can buildup in the engine’s cooling
system, causing damage over time. The DF150 and DF175
are equipped with two freshwater flush ports to make
flushing of the cooling system as convenient as possible.
One port located on the port side of the down housing and
a second located on the front panel provide easy access
and facilitate flushing of the system whether the boat is in
or out of the water.
Alternator Output
almost 80% of their
(A)
50
45
40
35
30
25
20
total output at a low
1,000 RPM. In most
cases, that’s enough
power to keep an
assortment of electron-
ics up and running.
15
10
5
0
1000
2000
3000
4000
5000
6000
(rpm)
■ Designed with Convenience
in Mind
Tilt Limit Switch
The motor tilt system incorporates a tilt limit switch
that prevents the motor from tilting beyond a predeter-
mined point. The system can be set by the user and can be
used to protect both the boat and motor from damage that
can occur when tilting the motor.
Fuse Box
Fuses protecting the
outboard’s electric system
are assembled into a single
fuse box located on the
side of the outboard motor.
This configuration offers
convenient access and
creates a clean exterior.
Fuse Box
Tilt Limit System
Water-cooled Voltage Regulator with
Isolator
Both outboards incorporate a water-cooled voltage
regulator which dissipates heat in the regulator to enhance
the engine’s durability.
The regulator also includes isolator function in the battery
charging system that allows use of two batteries. Electric
current is split into two circuits. If the sub battery becomes
drained, this system will safeguard the main battery.
6
DF150/175 SPECIFICATIONS
MODEL
DIMENSIONS
DF150
DF175
ENGINE TYPE
Four-Stroke DOHC 16 Valve
FUEL DELIVERY
SYSTEM
Multi Point Sequential Electronic Fuel Injection
TRANSOM HEIGHT
mm (in.)
L: 508 (20)
X: 635 (25)
STARTING SYSTEM
Electric
L: 211 (465.2)
X: 215 (474.0)
WEIGHT kg (Ibs.)
*Dry-weight, not including propeller
30
°
30
°
259.4 259.4
(10.2) (10.2)
NO. OF CYLINDERS
4
395.3
(15.6)
395.3
(15.6)
PISTON DISPLACEMENT
cm3 (cu.in.)
2,867 (174.9)
BORE × STROKE
m/m (in.)
677.8 (26.7)
167.6 (6.6)
1157.6 (45.6)
97 × 97 (3.81 × 3.81)
1038.2 (40.9)
671.3 (26.4)
MAXIMUM OUTPUT
HP (kW)
150 (110)
175 (129)
FULL THROTTLE
OPERATING RANGE rpm
5000-6000
5500-6100
STEERING
Remote
OIL PAN CAPACITY l
(U.S. / Imp. qt.)
8.0 (8.5/7.0)
IGNITION SYSTEM
ALTERNATOR
Fully-transistorized
12V 44A
ENGINE MOUNTING
TRIM METHOD
GEAR RATIO
Shear Mount
Power Trim and Tilt
2.50 : 1 (Two-stage Reduction Gear)
F.N.R
GEAR SHIFT
EXHAUST
Through Prop Hub Exhaust
Rubber Hub
DRIVE PROTECTION
PROPELLER SIZE (in.)
OPTIONAL
15-1/2 × 17
15-1/4 × 19
14-3/4 × 21
14-3/4 × 23
14-1/2 × 25
14-1/2 × 27
48.5(1.9)
Unit: mm (inch)
* Counter Rotation Model Available (Transom X only).
* Boats and motors come in a large variety of combinations.
See your authorized dealer for correct prop. selection to
meet recommended RPM range at W.O.T.
Please read your owners manual carefully. Remember,
boating and alcohol or other drugs don’t mix. Please operate
your outboard safely, responsibly and with respect for the
marine environment.
CARB Three-Star Label
The three-star label identifies
engines that meet the California
Air Resources Board’s 2008
exhaust emission standards.
Engines meeting these standards
have 65% lower emissions than
EPA 2006 exhaust emission
standards.
EPA 2006 Label
Suzuki’s four-stroke
technology ensure
compliance with EPA
2006 exhaust emission
standards set by the
U.S. Environmental
Protection Agency.
Equipment, specifications, colors, materials maybe subject
to change without notice.
Suzuki, the "S" logo, and Suzuki model names
are Suzuki trademarks or ®
DF150/175 Product Information (ASMC) 0504
Each model may be discontinued without notice. Please
inquire at your local dealer for details of any such changes.
Actual body colors may differ slightly from the colors in this
brochure.
99999-C2047-111
Printed in Japan
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