Suzuki DF175AP Specifications
| Engine Model: Suzuki DF175AP |
| Engine Type: 4-stroke inline 4-cylinder DOHC 16-valve gasoline outboard engine |
| Total Displacement: 175 cu.in (2.9 L) |
| Rated Engine Power: 175 Hp (128.7 kW) at 6000 rpm |
| Fuel System: Multi point sequential electronic fuel injection |
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The Suzuki DF175AP is a technologically
advanced 175 Hp outboard that sets a high standard in its class. It is
built around a large-displacement inline four-cylinder powerhead with a
2,867 cc displacement and a high 10.2:1 compression ratio, one of the
largest and most powerful in its class, delivering impressive
acceleration and low-end torque. The powerhead features a DOHC 16-valve
design with a maintenance-free self-adjusting timing chain.
The integration of the Suzuki Lean Burn Control System, utilizing an O2
sensor feedback loop, optimizes the air-fuel mixture for significant
fuel savings, particularly during cruising speeds, without sacrificing
throttle response or overall power delivery. A secondary balancer system
effectively counters inherent inline four-cylinder vibrations for
exceptionally smooth operation across the entire rpm range.
With features like Suzuki Precision Control drive-by-wire, Variable
Valve Timing (VVT), and an available Selective Rotation lower unit for
perfect twin-engine setups, the DF175AP is engineered to satisfy the
demands of serious boaters seeking a reliable, efficient, and
high-performing outboard.
Engine Model: Suzuki DF175AP
Engine Type: 4-Stroke, DOHC (Double Overhead Camshaft), 16-Valve
Number of Cylinders: In-Line 4
Valve Train Drive: Self-adjusting oil-bathed timing chain
Bore and Stroke: 97.0 mm x 97.0 mm (3.81 in x 3.81 in)
Piston Displacement: 2867 cc (175 cu. in)
Maximum Output: 128.7 kW (175 Hp)
Full Throttle Operating Range: 5500-6100 rpm
Idle Speed: 600-700 rpm
Fuel Delivery System: Multi-Point Sequential Electronic Fuel Injection
with Lean Burn Control
Alternator: 12V 44A
Trim Method: Power Trim and Tilt
Gear Ratio: 2.50:1
Gear Shift: F-N-R (Forward-Neutral-Reverse)
Control System: Suzuki Precision Control (Digital Drive-by-Wire)
Exhaust: Through Prop Hub Exhaust
Propeller Selection: 15"-27.5" (Standard Rotation)
Starting System: Electric with Suzuki Keyless Start System
Ignition System: Fully-transistorized
Engine Lubrication: Trochoid pump pressure lubrication
Engine Oil Capacity: 8.0 L (8.5/7.0 US/Imp. qt.)
Spark Plug: NGK LKR6E
Spark Plug Gap: Standard: 0.8-0.9 mm (0.031-0.035 in)
Valve clearance (Intake): 0.23-0.27 mm (0.009-0.011 in) (cold)
Valve clearance (Exhaust): 0.30-0.34 mm (0.012-0.013 in) (cold)
Fuel Type: Alcohol-free unleaded gasoline
Minimum Fuel Octane Rating: 87 (Research method)
Compression Ratio: 10.2:1
The DF175AP is built upon a robust inline four-cylinder block with a
large displacement of 2,867 cc, which the development team based on a
"big block" philosophy to deliver exceptional acceleration and velocity.
This substantial displacement is combined with a high compression ratio
of 10.2:1, drawing on Suzuki's extensive motorsports experience to
obtain great performance from a compact engine. The block is topped with
a DOHC powerhead that provides four valves per cylinder for optimal
airflow and combustion efficiency.
A key feature is the maintenance-free, self-adjusting oil-bathed timing
chain with an automatic hydraulic tensioner, ensuring precise valve
timing over the engine's life without requiring periodic adjustments.
The Variable Valve Timing (VVT) system, hydraulically controlled by oil
pressure, optimizes intake valve timing to maximize torque in the low
and mid-range, delivering powerful acceleration across the entire
powerband.
To neutralize the secondary vibration inherent to high-rpm operation in
inline four-cylinder engines, Suzuki engineers utilize a counter
balancer system. This system is divided into left and right sections,
each rotating in an opposite direction at twice the speed of the
crankshaft, effectively countering vibrations and producing remarkably
smooth engine operation.
The offset driveshaft design, pioneered by Suzuki, positions the
crankshaft in front of the driveshaft, moving the outboard's center of
gravity forward. This contributes greatly to the outboard's overall
compactness and improved weight distribution on the boat's transom,
while also reducing vibration by moving the engine's axis of inertia up
over the upper engine mount. A combination of soft-type and high-thrust
rubber mounts on both upper and lower mounts further reduces vibration
and provides stable operation under high loads.
The DF175AP's fuel system is highlighted by the Suzuki Lean Burn Control
System. This intelligent fuel delivery technology uses a 32-bit onboard
Engine Control Module (ECM) and an O2 sensor feedback loop to monitor
engine performance and operating conditions in real-time.
It predicts fuel needs and delivers a leaner, more precise fuel mixture
across the outboard's operating range, resulting in significant
improvements in fuel economy, especially in the cruising range where the
engine is used most of the time. When combined with Suzuki Precision
Control, it allows control of fuel and air flow to boost the limit of
the controllable revolution range, further improving fuel economy over a
wide operating range.
The Multi-Point Sequential Electronic Fuel Injection system precisely
meters fuel to each cylinder for optimal combustion. A Knock Sensor
monitors combustion to provide the ECM with information needed for
precise management of engine timing for optimum performance, maximizing
power output while also helping to increase engine durability.
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, helping to maintain optimum engine operating
efficiency across the engine's full operating range.
The DF175AP employs a trochoid pump pressure lubrication system to
ensure consistent pressurized oil delivery to all critical engine
components, including the crankshaft, connecting rods, and the valve
train with its VVT components. The engine has a substantial oil capacity
of 8.0 liters.
Engine temperature is managed by a reliable water-cooled system. A water
pump, located in the lower unit, draws water from the surrounding
environment and circulates it through water jackets in the cylinder
block and powerhead.
For post-operation maintenance, the Fresh Water Flushing System allows
easy connection of a garden hose to rinse salt, sand, and other debris
from the cooling passages, protecting the engine from corrosion. The
Suzuki Water Detecting System alerts the operator with both visual and
audio warnings if water is present in the fuel, preventing issues like
poor combustion, power loss, and corrosion.
| Mid Section and Lower Unit |
The mid-section houses the offset driveshaft, which contributes to the
engine's forward center of gravity and compact mounting footprint. The
lower unit features a robust gearcase designed for the innovative Suzuki
Selective Rotation system. This world-first technology incorporates a
special, unified design of gears, shafts, and bearings that allow the
outboard to operate reliably and efficiently in either standard or
counter-rotation direction.
For boats equipped with twin outboards, this eliminates the need to
purchase a dedicated counter-rotation model; the DF175AP can be switched
to counter-rotation mode by changing the gearshift mode and installing a
counter-rotation propeller.
The lower unit utilizes a two-stage gear reduction system designed to
take maximum advantage of the power produced by the high-performance
engine. Providing a final drive ratio of 2.50:1, one of the largest in
its class, it delivers powerful torque for quick acceleration and great
top-end speed.
The Multi-Stage Induction system ensures the engine gets the right
amount of air by utilizing two intake manifold pipes per cylinder, with
longer curved pipes for low-end torque and shorter direct pipes for
high-rpm power. Exhaust gases are channeled through the propeller hub
for quieter operation, and an intake resonator reduces air intake noise.
The Power Trim and Tilt (PTT) system provides hydraulic control over the
outboard's angle, allowing the operator to adjust boat trim for optimal
performance, fuel efficiency, and ride comfort. The Tilt Limit System
prevents the outboard from tilting beyond a selected angle, protecting
both the engine and boat from damage due to excessive tilting.
Proper trim angle adjustment is critical for maintaining steering
stability; too small an angle may cause the boat to "plow," while too
large an angle may cause "chine walk" or "porpoise," resulting in loss
of steering control.
The DF175AP is designed to work with a range of high-performance
stainless steel propellers to match various boat types and load
conditions. The recommended propeller pitch selection ranges from 15
inches to 27.5 inches for standard rotation models.
All propellers are of the three-blade type. The Watergrip Propeller,
featuring a new interchangeable square-shaped bush, offers efficient
conversion of engine power to propulsion resulting in better grip and
performance.
Transom Height (Long Shaft - L): 508 mm (20 in)
Transom Height (Extra Long Shaft - X): 635 mm (25 in)
Dry Weight (Long Shaft - L): 236 kg (520 lbs)
Dry Weight (Extra Long Shaft - X): 241 kg (530 lbs)
Engine Mounting: Shear Mount system with rubber dampers
Initial Service: Perform at 20 hours or 1 month
Engine Oil: Replace oil at every 100 hours or 12 months
Engine Oil Filter: Replace filter at every 200 hours or 12 months
Engine Oil Capacity: 8.0 L (8.5 US qt.) with filter
Gear Oil: Replace every 100 hours or 12 months
Gear Oil Capacity: As specified in the service manual
Spark Plugs Type: NGK LKR6E
Spark Plugs: Inspect every 100 hours or 12 months; replace every 300
hours or 36 months
Spark Plug Gap: Standard: 0.8-0.9 mm (0.031-0.035 in)
Spark Plug Torque: 20-25 Nm (15-18 lb-ft)
Valve Clearance (Intake): 0.23-0.27 mm (0.009-0.011 in) (cold)
Valve Clearance (Exhaust): 0.30-0.34 mm (0.012-0.013 in) (cold)
Low Pressure Fuel Filter: Replace every 100 hours or 12 months
High Pressure Fuel Filter: Replace every 400 hours or 2 years
Water Pump Impeller: Replace as needed; inspect regularly
Balancer Chain: Replace every 1600 hours
Valve Lash: Inspect every 300 hours or 36 months
Anodes (external): Inspect every 100 hours or 12 months
Battery: Check fluid level every 100 hours or 12 months
Fishing Boats: An ideal primary power source for bay boats, center
consoles, and bass boats in the 18 to 22-foot range, offering the
reliability, low-end grunt, and optional counter-rotation capability for
perfect twin-engine setups. Dual Console and Bowrider Boats: Provides
quiet, clean, and efficient power for family runabouts used for
cruising, tubing, and water sports.
Lightweight Cruisers and Deck Boats: Suitable for smaller cabin cruisers
and deck boats where a balance of power, weight, and fuel economy is
essential. Commercial and Work Applications: Its robust construction,
fuel efficiency, and corrosion resistance make it a dependable choice
for various light-duty commercial applications. Suzuki outboards are
used by commercial operators such as Sea Start and Solent RIB Charter,
testament to their reliability.
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