Suzuki DF140A Specifications
| Engine Model: Suzuki DF140A |
| Engine Type: 4-stroke inline 4-cylinder DOHC 16-valve gasoline outboard engine |
| Total Displacement: 124.7 cu.in (2 L) |
| Rated Engine Power: 140 Hp (103 kW) at 6000 rpm |
| Fuel System: Multi point sequential electronic fuel injection |
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The Suzuki DF140A is a technologically advanced
140 Hp outboard that sets a high standard in its class. It is built
around a proven 2,044 cc in-line four-cylinder powerhead, which benefits
from a 16-valve DOHC design and a maintenance-free timing chain. The
integration of the Lean Burn Control System, which utilizes an O2 sensor
feedback loop, allows the engine to optimize the air-fuel mixture for
significant fuel savings, particularly during cruising speeds, without
any sacrifice in throttle response or overall power delivery.
Weighing as little as 179 kg for the long shaft model, it boasts an
outstanding power-to-weight ratio. This engine is also notably refined,
with lower vibration levels and a tuned, throatier exhaust note compared
to earlier versions. With features like a two-stage gear reduction, an
adjustable electronic trim limiter, and the optional Troll Mode system,
the DF140A is engineered to satisfy the demands of both serious anglers
and families seeking a reliable and efficient outboard.
Engine Model: Suzuki DF140A
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: 86.0 mm x 88.0 mm (3.40 in x 3.50 in)
Piston Displacement: 2044 cc (124.7 cu. in)
Maximum Output: 103.0 kW (140 Hp)
Full Throttle Operating Range: 5600-6200 rpm
Fuel Delivery System: Multi Point Sequential Electronic Fuel Injection
Alternator: 12V 40A
Trim Method: Power Trim and Tilt
Gear Ratio: 2.59:1
Gear Shift: F-N-R (Electronic)
Control System: Remote steering; tiller kit optional
Exhaust: Through Prop Hub Exhaust
Propeller Selection: 15" - 25" pitch
Starting System: Electric
Ignition System: Fully-transistorized
Engine Lubrication: Wet sump
Engine Oil Capacity: 5.5 L (5.8 US qt)
The DF140A is built upon a robust in-line four-cylinder block with a
displacement of 2044 cc. This powerplant is designed to deliver high
output and efficient operation. The powerhead features a
high-performance 16-valve, dual overhead cam (DOHC) configuration that
ensures optimal airflow and combustion efficiency.
A key feature is the self-adjusting, oil-bathed timing chain, which is
equipped with an automatic hydraulic tensioner, eliminating the need for
routine maintenance and ensuring precise valve timing over the engine's
life.
The engine also employs an offset driveshaft design, which positions the
powerhead forward of the driveshaft, shifting the center of gravity
forward. This results in a more compact mounting footprint and improved
weight distribution on the boat's transom, enhancing handling and
performance.
The fuel system of the DF140A is highlighted by the Suzuki Lean Burn
Control System. This advanced technology uses an O2 sensor feedback
system to constantly monitor engine operating conditions, allowing the
engine to run on a leaner, more efficient fuel mixture during cruising
speeds. This optimization provides significant improvements in fuel
efficiency, with savings of up to 14 percent depending on conditions.
The system works in concert with the Multi-Point Sequential Electronic
Fuel Injection, which delivers a precise and optimized air-fuel mixture
to each cylinder for immediate throttle response, smooth acceleration,
and reduced emissions. A knock sensor is also incorporated to detect and
control abnormal combustion, thereby optimizing engine performance and
enhancing reliability. To protect the fuel system from contamination,
the Suzuki Water Detecting System alerts the operator with visual and
audio warnings if water is present in the fuel.
The DF140A utilizes a dependable wet sump lubrication system. A trochoid
oil pump ensures that pressurized oil is delivered to all critical
moving parts within the engine. The engine has a total oil capacity of
5.5 liters.
A low oil pressure caution system is integrated to alert the operator to
potential lubrication issues, helping to safeguard the engine. Regular
oil changes, using high-quality 4-stroke outboard oil meeting NMMA FC-W
certification, are fundamental to the maintenance schedule.
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. The DF140A was the first four-stroke outboard to
utilize an oil cooler, ensuring consistent engine performance under all
operating conditions.
A significant feature for longevity is the Fresh Water Flushing System,
which includes a dedicated flush port that allows owners to easily
connect a garden hose to rinse salt, sand, or other debris from the
cooling passages after use, protecting the engine from corrosion and
blockages.
| Mid Section and Lower Unit |
The mid-section houses the offset driveshaft, which contributes to the
engine's forward center of gravity. The lower unit features a robust
gearcase with a two-stage gear reduction system.
The high 2.59:1 gear ratio enables the engine to swing larger
propellers, translating its power into strong, efficient thrust for
excellent hole-shot and the ability to push heavier loads effectively.
The gearcase also includes a speedometer pickup as a standard feature.
Exhaust gases are channeled through the propeller hub, contributing to
quieter operation.
The Power Trim and Tilt (PTT) system provides hydraulic control over the
outboard's angle, allowing the operator to adjust the boat's trim for
optimal performance, fuel efficiency, and ride comfort.
The system on the DF140A is a three-cylinder type. A notable feature is
the adjustable Electronic Trim Limiter, which can be pre-set by the
operator to prevent the outboard from being tilted beyond a desired
point, protecting both the outboard and the boat from potential contact
damage. For operation in shallow water or for trailering, the motor can
be tilted up beyond the normal trim range.
The DF140A is designed to work with a range of propellers to match
various boat types and load conditions. The recommended propeller pitch
selection generally ranges from 15 inches to 25 inches. A wider
selection, including various diameters and pitches for both standard and
counter-rotation applications, is available to fine-tune performance.
Selecting the correct propeller is essential to allow the engine to
operate within its designated full-throttle range of 5600-6200 rpm,
ensuring maximum performance, fuel efficiency, and engine longevity.
Transom Height (Long Shaft): 508 mm (20 in)
Transom Height (Extra Long Shaft): 635 mm (25 in)
Dry Weight (Long Shaft): 179 kg (395.7 lbs)
Dry Weight (Extra Long Shaft): 184 kg (406.8 lbs)
Engine Mounting: Shear mount system
Engine Oil Capacity: 5.5 L (5.8 US qt) with filter.
Recommended Oil: High-quality 4-stroke outboard oil, NMMA FC-W
certified.
Spark Plug: Refer to owner's manual for specific model.
Spark Plug Gap: As specified in the service manual.
Gearcase Oil Capacity: Information available in service manual.
Water Pump Impeller: Inspection and potential replacement recommended
annually.
Maintenance Features: The self-adjusting timing chain is
maintenance-free. The Fresh Water Flushing System simplifies post-use
cleanup. The Water Detecting System provides an alert for water in the
fuel. An optional Troll Mode system allows for precise control of
trolling speeds in 50 rpm increments.
Connecting Rod Nuts: 16-18 Nm (12-13 lb-ft).
Flywheel Nut: 130-140 Nm (96-103 lb-ft).
Spark Plugs: 20-25 Nm (15-18 lb-ft).
Propeller Nut: 35-55 Nm (26-41 lb-ft).
Oil Drain Plug (Engine): 23-27 Nm (17-20 lb-ft).
Gearcase Oil Drain/Fill Screws: 7-10 Nm (5-7 lb-ft).
Power Trim and Tilt Motor Assembly Bolts: 23-27 Nm (17-20 lb-ft).
Fishing Boats: An ideal primary power source for bay boats, center
consoles, and tiller-steer models in the 18 to 22-foot range, offering
the reliability, low-end grunt, and optional Troll Mode needed for
serious fishing. Pontoon Boats: A popular choice for powering pontoon
boats, where its strong torque provides excellent acceleration and
efficient cruising for leisurely days on the water. 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. Twin-Engine Installations: Its low weight and compact
proportions make it an excellent choice for twin installations on many
larger trailer boats, offering combined power with significant transom
weight savings.
Commercial and Work Applications: Its robust construction, fuel
efficiency, and corrosion resistance also make it a dependable choice
for various light-duty commercial applications. Saltwater Use:
Extensively protected by Suzuki's multi-layer Anti-Corrosion Finish,
which includes epoxy resin and multiple paint layers, it is engineered
to withstand the corrosive effects of the saltwater environment,
ensuring long-term durability and a high-quality appearance. It also
meets CARB 3-Star Ultra-Low emissions standards.
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