Suzuki DF6AS Specifications
| Engine Model: Suzuki DF6AS |
| Engine Type: 4-stroke 1-cylinder short shaft gasoline outboard engine |
| Total Displacement: 8.4 cu.in (138 cc) |
| Rated Engine Power: 6 Hp (4.4 kW) at 5750 rpm |
| Fuel System: Carburetor |
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The Suzuki DF6AS is recognized for its
significant reduction in weight compared to its predecessor, enhancing
its portability for users who frequently transport and store their
engine. Weighing as little as 24.0 kg in its short-shaft version, it
incorporates design elements that improve the user experience, such as a
well-placed carrying handle and a redesigned fuel system.
The integrated one-liter fuel tank is positioned above the carburetor,
allowing for gravity feed and easier starting after the engine has been
stored. Its operation is noted for a smooth idle, linear power delivery,
and reduced vibration at the tiller, particularly in the mid-range. The
engine is built with Suzuki's anti-corrosion system for durability in
marine environments and includes features like a digital CDI ignition
for reliable starting and an over-revolution limiter for protection.
As a four-stroke, it offers cleaner operation and greater fuel
efficiency compared to traditional two-stroke engines. A specific damper
in the tiller joint effectively mitigates vibration transmission, making
boat operation more comfortable. The engine also allows for convenient
three-way storage without oil leakage, addressing a common concern with
portable outboards.
Engine Model - Suzuki DF6AS
Engine Type - 4-stroke single-cylinder OHV gasoline outboard engine
Number of Cylinders - 1
Displacement - 138 cc (8.42 cu-in)
Cylinder Bore - 60.4 mm (2.38 in)
Piston Stroke - 48.0 mm (1.89 in)
Maximum Engine Power - 4.4 kW (6.0 hp)
Full Throttle Operating Range - 4750 - 5750 r/min
Idle Speed - 1250 - 1350 r/min
Fuel System Type - Carburetor
Fuel Type - Unleaded gasoline (91 octane minimum)
Ignition System - Digital CDI
Cooling System - Water-cooled with thermostat
Exhaust System - Through propeller hub
Starting System - Manual
Choke System - Manual
Gear Shift - Forward - Neutral - Reverse
Gear Ratio - 1.92:1
Steering System - Tiller
Trim and Tilt System - Manual, 5-position tilt pin
Transom Height (Short) - 381 mm (15 in)
Dry Weight (Short Shaft) - 24.0 kg (52.8 lbs)
The powerhead is built around a single-cylinder configuration with a
displacement of 138 cc. It utilizes an OverHead Valve (OHV) design with
two valves per cylinder, one for intake and one for exhaust. A notable
engineering feature is the offset cylinder design, where the crankshaft
is positioned slightly off the center of the cylinder bore. This reduces
the lateral force (side thrust) of the piston against the cylinder wall
during the power stroke.
The result is smoother piston movement, reduced friction, and enhanced
operational efficiency. The valve train is designed for quiet operation,
with engineering refinements to the rocker arm structure to minimize
excessive movement and noise.
The adoption of a plain bearing for the crankshaft instead of a common
ball type further contributes to noise reduction. The cylinder head is
secured with bolts that require a precise tightening torque of 21.7
lbf-ft (30 Nm) during service or reassembly. Valve lash, critical for
proper engine timing and noise control, is set to 0.13-0.17 mm
(0.005-0.007 in) for both the intake and exhaust valves.
The DF6AS features a straightforward and reliable fuel delivery system
centered on a carburetor. A mechanical fuel pump draws fuel from either
the built-in 1.0-liter tank or an optional external remote tank,
selected via a changeover cock on the engine. A significant upgrade in
this model is the positioning of the integral fuel tank. Mounted high on
the engine, it allows gravity to feed fuel to the carburetor.
This design eliminates the need for a primer bulb to re-fuel the system
after the engine has not been used for a while, simplifying the starting
procedure. A manual choke is provided for cold starts. The fuel system
also includes a fuel filter that requires periodic inspection and
replacement to ensure contaminant-free operation. The one-way valve in
the fuel circuit maintains system prime, enabling quick starting even
after extended storage.
The lubrication system is a trochoid pump-driven forced system, a design
that enhances reliability. It is engineered to deliver a steady supply
of oil under pressure to critical engine components, including the upper
crankshaft bearing and the big end of the connecting rod, reducing wear
and aiding in cooling. A noteworthy feature in this class of outboard is
the inclusion of a replaceable, cartridge-style oil filter, which
significantly improves the system's long-term reliability by trapping
contaminants.
An oil level window is provided on the side of the engine for easy
visual checks of the oil level. This advanced lubrication system also
provides the practical benefit of allowing the outboard to be stored on
its port, starboard, or front side without risk of oil leakage. The
engine oil capacity is 0.70 liters (0.75 quarts), and it requires SAE
10W-30 or 10W-40 oil meeting API service classifications SH through SN.
Engine temperature is managed by a conventional water-cooling system.
Water is drawn into the engine through intakes located on the gearcase,
just below the anti-ventilation plate. A rubber impeller water pump,
driven by the driveshaft, pushes this water through the engine block to
absorb heat. A thermostat regulates the water flow to maintain optimal
operating temperature for efficiency and performance.
A tell-tale port, or indicator, provides a visible stream of water to
confirm that the cooling system is functioning correctly. An overheat
protection system is integrated into the engine control unit to reduce
the risk of engine seizure in the event of a cooling system failure. The
system also incorporates a freshwater flushing attachment, allowing
owners to easily rinse out saltwater and debris after use to prolong the
engine's life.
| Mid Section and Lower Unit |
The mid-section houses the driveshaft and provides the mounting point
for the engine to the transom bracket. The lower unit contains the
gearcase, which is filled with 0.19 liters (0.20 quarts) of Suzuki
Outboard Motor Gear Oil or SAE 90 GL5 gear oil. The gears facilitate a
reduction ratio of 1.92:1, optimizing propeller speed for thrust.
The exhaust is expelled through the propeller hub, which also helps to
quiet engine operation. The shift mechanism allows for positive
engagement of Forward, Neutral, and Reverse gears. The anti-ventilation
plate, just above the propeller, aids in holding the boat on plane and
preventing air from being drawn into the propeller.
Trim and tilt adjustments are performed manually. The engine is equipped
with a manual tilt system that uses a pin in one of several adjustment
holes on the transom bracket. This allows the operator to select from
five different trim positions to optimize the boat's running angle for
various loads and water conditions.
For tilting the engine out of the water for beaching, trailering, or
storage, a release lever disengages the lock, allowing the engine to
tilt up. The system has been refined to lock securely in three different
positions when raised and to lower smoothly without catching when
released. Grease fittings are provided on the pivot points of the clamp
bracket to prevent seizing and ensure smooth operation over time.
The DF6AS is designed to use three-bladed aluminum propellers. The
propeller diameter is 190 mm (7.5 in). To accommodate different boat
types and loading conditions, two primary propeller pitches are
available: 165 mm (6.5 in) and 178 mm (7.0 in).
The 6.5-inch pitch propeller provides more low-end thrust, which is
beneficial for heavier boats or those needing to get on plane quickly.
The 7.0-inch pitch propeller is better suited for lighter boats where a
higher top speed is desired. The standard propeller specified for many
applications is the 3 x 7.5 x 6.5 configuration. The propeller selection
range extends from 6 to 7 inches of pitch.
The short shaft model, designed for a 381 mm (15 in) transom, has a dry
weight of 24.0 kg (52.8 lbs).
The overall height of the short shaft model is 1095 mm.
Every 100 hours of operation or annually, the following tasks should be
performed: change engine oil, change gear oil, check and clean the spark
plug (adjusting the gap to 0.8-0.9 mm or 0.031-0.035 in), inspect the
fuel line and fuel filter, check the condition of the sacrificial
anodes, verify thermostat operation, and check the carburetor, propeller
nut, and cotter pin.
Every 200 hours, in addition to the 100-hour checks, the engine requires
replacement of the oil filter, inspection and adjustment of valve lash,
checking and adjusting the idle speed, and inspecting the water pump and
its impeller.
Every 300 hours, the spark plug should be replaced with an NGK CPR6EA-9,
and the water pump impeller must be replaced to prevent cooling system
failure. Every 400 hours, the in-line fuel filter should be replaced.
The Suzuki DF6AS is intended for a wide variety of small watercraft. Its
lightweight and portable nature make it an ideal power source for small
fishing boats, dinghies, tenders for larger yachts, and inflatable
boats. It is a popular choice as a reliable auxiliary or "kicker" motor
for sailboats or larger fishing vessels, providing a source of
slow-speed maneuvering power and a backup should the main engine fail.
Its power output of 6 hp places it at the threshold for which many
jurisdictions do not require a boating license, broadening its appeal to
recreational users. Beyond traditional boats, its portability makes it
suitable for powering craft like duck boats or small skiffs used in
sheltered waters. It is also well-suited for commercial fishing
applications and service craft where reliability and ease of use are
paramount.
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