Suzuki DF140BTX Specifications
| Engine Model: Suzuki DF140BTX |
| 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 DF140BTX is a refined and
technologically advanced 140 Hp outboard that delivers a compelling
combination of performance, efficiency, and user-friendly features in a
package designed for 25-inch transoms. 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 DF140BTX is engineered to provide a premium and worry-free
boating experience.
Engine Model: Suzuki DF140BTX
Engine Type: 4-Stroke, DOHC (Double Overhead Camshaft), 16-Valve,
In-Line 4 Cylinder
Number of Cylinders: 4
Valve Train Drive: Self-adjusting oil-bathed timing chain with automatic
hydraulic tensioner
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 ; also cited as 5600-6200
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" pitch (Standard 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) / 87 AKI
Compression Ratio: 10.6:1
The DF140BTX is built upon a robust inline four-cylinder block with a
displacement of 2045 cc, the key element of this model. A key
advancement is the increase in the compression ratio to 10.6:1, achieved
through extensive simulation and testing of over 1,000 combinations of
port, piston, and masking. This higher ratio 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, rendering it 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, improved weight distribution, and more stable steering
performance.
The DF140BTX'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 O2 Sensor Feedback Control
system helps maintain optimum engine operating efficiency across the
engine's full operating range.
The DF140BTX 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, open-loop
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 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.
Standard on this model is the Suzuki Micro Plastic Collector (MPC), an
innovative device that filters micro-plastics from the cooling water
discharge as part of Suzuki's Clean Ocean Project, without affecting
engine performance. 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.
0The 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 DF140BTX 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 this standard rotation
model.
Suzuki recommends an aluminum propeller for single-engine installations
and a stainless steel Watergrip propeller for twin installations to
optimize performance. An optional Troll Mode System is available,
providing precise control over engine speed in low rpm ranges,
adjustable in 50 rpm increments.
Transom Height (Extra Long Shaft - X): 635 mm (25 in)
Dry Weight (Extra Long Shaft - X): 190-194 kg (419-428 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.
Lubrication Points: Apply marine-grade water-resistant grease to
steering bracket, swivel bracket, and propeller shaft annually.
Battery: Minimum recommended specifications apply.
Cylinder Head Bolts: 36 lb-ft (49 Nm)
Connecting Rod Bolts: 28 lb-ft (38 Nm)
Flywheel Nut: 22 lb-ft (30 Nm)
Spark Plugs: 18 lb-ft (24 Nm)
Engine Oil Drain Plug: 12 lb-ft (16 Nm)
Gear Oil Drain/Fill Screws: 12 lb-ft (16 Nm)
Propeller Nut: 26 lb-ft (35 Nm)
Offshore Fishing Boats: An excellent primary power source for larger
center consoles, bay boats, and walk-around cuddy cabins in the 18 to
24-foot class, designed for offshore fishing applications. The Atomic 22
Offshore Edition, powered by twin Suzuki DF140BTX outboards,
demonstrates serious offshore power and range, achieving a top speed of
42 knots and accelerating from 0-25 knots in just 9.2 seconds.
Larger Rigid Inflatable Boats (RIBs): Powers high-performance RIBs and
sports boats used for coastal cruising and commercial applications. Dual
Console and Bowrider Boats: Provides refined and efficient power for
larger family runabouts used for cruising 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. Twin-Engine Installations: Frequently used in twin
configurations on larger hulls to provide combined power, enhanced
maneuverability, and redundancy.
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