Suzuki DF140B Specifications
| Engine Model: Suzuki DF140B |
| Engine Type: 4-stroke inline 4-cylinder DOHC 16-valve gasoline outboard engine |
| Total Displacement: 124.8 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 DF140B is a refined and
technologically advanced 140 Hp outboard that delivers a compelling
combination of performance, efficiency, and user-friendly features. The
increase in the compression ratio to 10.6:1 is a key advancement,
contributing to improved top speed, quicker acceleration, and enhanced
thermal efficiency compared to the previous DF140A model.
The engine is packed with features like the Suzuki Lean Burn Control
System, Variable Valve Timing, and a redesigned cowling with an advanced
air intake and resonator for ultra-quiet operation. With its emphasis on
reliability, ease of maintenance, and a host of thoughtful design
details, the DF140B is engineered to provide a premium and worry-free
boating experience.
Engine Model: Suzuki DF140B
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 (3.39 in x 3.46 in)
Piston Displacement: 2045 cc (124.8 cu. in)
Maximum Output: 103.0 kW (140 Hp)
Full Throttle Operating Range: 5700-6300 rpm
Fuel Delivery System: Multi-Point Sequential Electronic Fuel Injection
Alternator: 12V 40A
Steering: Remote
Trim Method: Power Trim and Tilt
Gear Ratio: 2.59:1
Gear Shift: F-N-R (Forward-Neutral-Reverse)
Control System: Mechanical
Propeller Selection: 15"-25" (Standard Rotation); 17"-23" (Counter
Rotation)
Starting System: Electric
Ignition System: Fully-transistorized
Engine Lubrication: Trochoid pump pressure lubrication
Engine Oil Capacity: 5.5 L (5.8/4.8 US/Imp. qt.)
Gear Oil Capacity: 1.05 L (1.11/0.92 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): 0.33-0.37 mm (0.013-0.015 in) (cold)
Fuel Type: Alcohol-free unleaded gasoline
Minimum Fuel Octane Rating: 91 (Research method)
Compression Ratio: 10.6:1
The DF140B is built upon a robust inline four-cylinder block with a
displacement of 2045 cc. A key advancement for this model is the
increase in the compression ratio to 10.6:1. Through extensive
simulation and testing, engineers achieved this higher ratio, which is a
primary contributor to the engine's improved top speed, quicker
acceleration, and greater thermal efficiency.
The powerhead features a DOHC 16-valve configuration for optimal airflow
and combustion efficiency. The valve train is driven by a self-adjusting
oil-bathed timing chain, which runs in an oil bath and is equipped with
an automatic hydraulic tensioner. This design renders the timing chain
maintenance-free for the life of the engine. The Variable Valve Timing
(VVT) system is hydraulically controlled by oil pressure and
automatically optimizes intake valve timing to deliver strong, smooth
torque and impressive acceleration across the entire powerband.
The offset driveshaft design positions the powerhead closer to the
front, moving the outboard's center of gravity forward. This
configuration results in reduced vibration, a more compact mounting
footprint, and more stable steering performance.
The DF140B's fuel system is centered around the Suzuki Lean Burn Control
System. This intelligent technology uses an O2 sensor feedback loop to
monitor engine operating conditions in real-time, predicting fuel needs
and delivering a precise, optimized air-fuel mixture. This system
provides significant improvements in fuel economy across all speed
ranges, most notably at cruising speeds.
The Multi-Point Sequential Electronic Fuel Injection system precisely
meters fuel to each cylinder for optimal combustion, ensuring crisp
throttle response, smooth acceleration, and reduced emissions. The
engine management system also incorporates a knock sensor to monitor
combustion, allowing the ECU to adjust timing for optimum performance
and to help increase engine durability.
The DF140B 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 an oil capacity of 5.5 liters.
A new oil filter location and the addition of an oil spill catcher on
the filter mount are key maintenance-focused design improvements,
allowing for cleaner and easier oil changes by simply removing the top
cowling and preventing spillages. The hole for the oil level gauge has
been widened to 15mm to accommodate a larger oil change hose.
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 DF140B was the first four-stroke outboard to
utilize an oil cooler, ensuring consistent engine performance under all
operating conditions.
The cooling system benefits from a dual water inlet design. By
positioning water intakes at two locations, the system ensures a greater
water supply at high speeds while also allowing for effective operation
in shallow water conditions, protecting the engine from overheating.
For post-operation maintenance, the Dual Engine Flush Port system allows
for 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 utilizes a water-detecting fuel filter
to alert the operator with both visual and audio warnings if water is
present in the fuel, thereby preventing issues like poor combustion,
power loss, and internal corrosion.
| Mid Section and Lower Unit |
The mid-section houses the offset driveshaft, contributing to the
forward center of gravity and overall compactness. The lower unit
features a robust gearcase with a 2.59:1 gear ratio, one of the largest
in its class, achieved through a 2-stage gear reduction system.
This system, enabled by the offset driveshaft, provides a first stage
reduction between the crankshaft and driveshaft and a second stage
reduction inside the gear case. The higher gear ratio allows the engine
to turn larger diameter propellers, resulting in powerful torque for
quick acceleration, high propulsive efficiency, and the ability to
maintain thrust even under heavy loads.
With the optimization of the gear oil passage, the gear oil temperature
is lowered, cooling the gear which contributes to increasing the
durability of the pinion gear. Exhaust gases are channeled through the
propeller hub for quieter operation. A new silencer and resonator system
integrated into the design further reduces engine noise at all speeds.
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 includes a Tilt Limit System, which features a
user-adjustable tilt limit switch that prevents the outboard from
tilting beyond a predetermined angle, thereby protecting both the engine
and the boat from damage that can be caused by excessive tilting.
The DF140B is designed to work with a range of propellers to match
various boat types and load conditions. The recommended propeller pitch
selection ranges from 15 inches to 25 inches for standard rotation
models, and from 17 inches to 23 inches for counter-rotation
applications.
All propellers are of the three-blade type. An optional Troll Mode
System is available, providing precise control over engine speed in low
rpm ranges from idle up to 1200 rpm in 50 rpm increments, ideal for
trolling.
Transom Height (Long Shaft - L): 508 mm (20 in)
Transom Height (Extra Long Shaft - X): 635 mm (25 in)
Dry Weight (Long Shaft - L): 186 kg (410 lbs)
Dry Weight (Extra Long Shaft - X): 190 kg (419 lbs)
Engine Mounting: Shear Mount system
Engine Oil Capacity: 5.5 L with filter
Recommended Engine Oil: High-quality 4-stroke motor oil, NMMA FC-W
certified
Gear Oil Capacity: 1.05 L
Spark Plugs: 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); inspect
periodically
Valve Clearance (Exhaust): 0.33-0.37 mm (0.013-0.015 in) (cold); inspect
periodically
Water Pump Impeller: Inspect and replace as needed
Anodes (external): Inspect periodically; replace when eroded
Connecting Rod Nuts: 16-18 Nm (12-13 lb-ft).
Crankshaft Bearing Cap Bolt: 50-55 Nm (37-41 lb-ft).
Flywheel Nut: 130-140 Nm (96-103 lb-ft).
Spark Plugs: 20-25 Nm (15-18 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).
Propeller Nut: 35-55 Nm (26-41 lb-ft).
Power Trim and Tilt Motor Assembly Bolts: 23-27 Nm (17-20 lb-ft).
The Suzuki DF140B is an exceptionally versatile outboard, ideally suited
for a wide range of mid-sized to larger boats where a combination of
smooth power, advanced technology, and quiet operation is desired.
Fishing Boats: An excellent primary power source for bay boats, side
consoles, and center consoles in the 16 to 24-foot class, designed for
freshwater, inshore, and offshore fishing applications.
Its performance on twin-engine rigs is well-regarded. Dual Console and
Bowrider Boats: Provides refined 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 advanced features is
essential. Commercial and Work Applications: Its robust construction,
fuel efficiency, and advanced reliability make it a dependable choice
for various light-duty commercial applications.
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