Suzuki DF20AS Specifications
| Engine Model: Suzuki DF20AS |
| Engine Type: 4-stroke 2-cylinder short shaft gasoline outboard engine |
| Total Displacement: 20.1 cu.in (327 cc) |
| Rated Engine Power: 20 Hp (14.7 kW) at 6300 rpm |
| Fuel System: Multi-point sequential electronic fuel injection |
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The Suzuki DF20AS is a technologically advanced
portable outboard that sets new standards in its class. Its
groundbreaking Battery-Less Electronic Fuel Injection system operates
without the need for a battery, an industry first in this Hp class,
ensuring reliable starting and smooth running performance while shedding
unnecessary weight. The addition of Suzuki's proven Lean Burn Control
technology monitors engine performance and operating conditions to
deliver the optimal air-fuel mixture, resulting in significant fuel
savings and reduced emissions throughout the operating range.
The engine features an Easy Start recoil system with exceptionally light
pull effort, enabled by two decompressors positioned on the camshaft.
Built with Suzuki's advanced anti-corrosion system featuring special
aluminum surface treatment for durability in marine environments, the
DF20AS offers user-friendly operation combined with state-of-the-art
engineering. At just 44 kg, it is the lightest outboard in its class,
making it an ideal power source for small fishing boats, inflatables,
and as a dependable auxiliary engine.
Engine Model - Suzuki DF20AS, DF20AES, DF20ARS, DF20ATS, DF20ATHS
Engine Type - 4-stroke two-cylinder OHC gasoline outboard engine
Number of Cylinders - 2
Displacement - 327 cc (20.1 cu-in)
Cylinder Bore - 60.4 mm (2.38 in)
Piston Stroke - 57.0 mm (2.24 in)
Maximum Engine Power - 14.7 kW (20.0 hp)
Full Throttle Operating Range - 5300 - 6300 r/min
Idle Speed - 800 - 900 r/min
Fuel System Type - Multi-Point Sequential Electronic Fuel Injection with
Lean Burn Control
Fuel Pump Type - Integral with battery-less operation
Fuel Type - Unleaded gasoline (91 octane minimum)
Ignition System - Digital CDI
Cooling System - Water-cooled with thermostat and Fresh Water Flushing
System
Exhaust System - Through propeller hub
Starting System - Manual recoil
Choke System - Automatic via EFI system
Gear Shift - Forward - Neutral - Reverse
Gear Ratio - 2.08:1
Steering System - Tiller Handle
Trim and Tilt System - Manual Trim and Tilt, 5 tilt pin positions
Transom Height (Short Shaft) - 381 mm (15 in)
Dry Weight (Manual Start) - 44.0 kg (97.0 lbs)
Alternator Rating - 12V 6A
The powerhead is constructed around an inline two-cylinder configuration
with a displacement of 327 cc. The engine is a 4-stroke cycle gasoline
unit featuring OHC valve mechanism with two valves per cylinder. The
cylinder bore inside diameter measures 60.400-60.415 mm, with a maximum
permissible out-of-round of 0.050 mm. The piston skirt diameter is
60.365-60.380 mm, resulting in a piston-to-cylinder clearance of
0.0271-0.0425 mm. The piston pin outside diameter is 15.995-16.000 mm,
with a piston pin bore inside diameter of 16.002-16.008 mm, providing a
clearance of 0.002-0.013 mm.
The connecting rod big end inside diameter is 29.025-29.034 mm, with a
crank pin outside diameter of 28.989-29.000 mm, resulting in an oil
clearance of 0.025-0.045 mm. Connecting rod side clearance at the big
end is 0.100-0.250 mm. The crankshaft journal outside diameter is
31.989-32.000 mm with an oil clearance of 0.020-0.047 mm. Maximum
crankshaft runout is 0.040 mm and crankshaft thrust play is 0.6 mm.
The piston rings include a top ring, second ring, and oil ring. The top
ring has a width of 1.02-1.04 mm and an end gap of 0.12-0.25 mm. The
second ring width is 1.21-1.23 mm with an end gap of 0.26-0.39 mm. Top
ring side clearance is 0.030-0.070 mm, while second ring side clearance
is 0.02-0.06 mm. Engine mounting utilizes a shear mount design to
isolate and dampen vibration from the hull.
The cylinder head incorporates the OHC valve train with two valves per
cylinder. The OHC is mounted over the cylinder head and driven by the
crankshaft through a timing belt. The cylinder head warp limit is 0.050
mm. Minimum valve head thickness for both intake and exhaust valves is
0.50 mm.
The intake valve stem outside diameter is 5.475-5.490 mm, while the
exhaust valve stem is 5.450-5.465 mm. Valve guide inside diameter for
both valves is 5.500-5.512 mm. Intake valve stem-to-guide clearance is
0.010-0.037 mm, and exhaust clearance is 0.035-0.062 mm. Valve seat
width for both intake and exhaust is 0.9-1.1 mm. The valve spring free
length is 33.16 mm.
Intake cam height is 23.710-23.870 mm, while exhaust cam height is
23.530-23.690 mm. Camshaft journal outside diameter is 24.959-24.980 mm
for the upper journal and 22.959-22.980 mm for the lower, with an oil
clearance of 0.020-0.062 mm. Valve lash is set to 0.16-0.20 mm for both
intake and exhaust valves.
The DF20AS features a revolutionary Multi-Point Sequential Electronic
Fuel Injection system that operates without a battery, an industry first
in this Hp class. All-new components including an inline high-pressure
fuel pump, fuel cooler, vapor separator, fuel injectors, and a new
throttle body were designed to be as compact and lightweight as
possible. The system provides quicker starts, smoother running
performance, and superior acceleration in all operating conditions.
Suzuki's Lean Burn Control technology predicts fuel requirements based
on operating conditions and delivers the optimal air-fuel mixture to the
engine, resulting in remarkable fuel economy throughout the operating
range. A standard 12-liter external fuel tank is included with the
engine. The engine is designed to run on unleaded gasoline with a
minimum octane rating of 91.
The lubrication system is a pressure-fed wet sump design utilizing a
trochoid-type cam-driven oil pump to ensure reliable oil delivery to all
critical engine components. This pressurised system reduces friction and
wear, enhancing engine longevity. The engine includes a replaceable
cartridge-style oil filter.
The oil filter is located behind a round cover secured by three bolts,
accessible after removing the side cover and blue fuel filter from the
left side of the motor. Engine oil capacity is 1.00 liter of SAE 10W-30
or 10W-40 oil, meeting API service classifications SG through SN. A low
oil pressure warning system with LED indicator protects the engine from
operation with insufficient oil pressure.
Engine temperature is regulated by a water-cooled system with a
thermostat. A heat exchanger helps maintain constant engine temperature
to prevent overheating. Cooling water is drawn into the engine through
intakes on the gearcase and circulated by a rubber impeller water pump.
The Fresh Water Flushing System allows owners to easily flush cooling
passages with fresh water after use in salt or polluted water. An
overheat warning system alerts the operator to cooling system
malfunctions. A tell-tale port provides visible confirmation that the
cooling system is operational.
| Mid Section and Lower Unit |
The mid-section houses the driveshaft and provides the mounting
interface to the transom bracket. The engine mounting utilizes a shear
mount design to isolate and dampen vibration from the hull. The lower
unit contains the gearcase, which is filled with 0.25 liters of Suzuki
Outboard Motor Gear Oil or GL5 SAE 90 gear oil.
The gears provide a reduction ratio of 2.08:1, optimizing propeller
speed for effective thrust. The shift mechanism enables smooth and
positive engagement of Forward, Neutral, and Reverse gears. Exhaust
gases are expelled through the propeller hub for quieter operation.
Trim and tilt adjustments are performed manually with 5 tilt pin
positions. The manual trim system uses a pin in one of several
adjustment positions on the transom bracket, allowing the operator to
select the optimal trim angle for the boat's running attitude under
various load and water conditions.
A tilt release lever disengages the lock for tilting the engine out of
the water for beaching, trailering, or storage. The tiller handle
features an optimized grip design with exclusive material for improved
hand adhesion, and an added weight reduces vibration during navigation
for enhanced comfort.
The DF20AS is designed to use three-bladed aluminum propellers. The
standard propeller diameter is 235 mm (9.25 in). A wide range of
propeller pitches is available from 7 inches to 12 inches to accommodate
different boat and loading conditions.
Common pitch options include 7, 9, 10, 11, and 12 inches. The standard
propeller supplied is a 3 x 11-1/4 x 15" model according to some
specifications. Selecting the correct pitch is crucial for allowing the
engine to operate within its recommended full-throttle RPM range of
5300-6300 for optimal performance and efficiency.
Portability combined with advanced technology defines the DF20AS.
Designed for a 381 mm (15 in) transom, the manual start tiller model has
a dry weight of only 44.0 kg (97.0 lbs). An integrated carrying handle
allows for convenient transport.
The innovative technology used in the DF20AS makes this the lightest
outboard in its class. Overall dimensions are designed for compact
storage and easy handling. Electric start short shaft models are also
available weighing 48.0 kg (105.7 lbs).
Every 100 hours of operation or annually, the following tasks should be
performed: change engine oil, change gear oil, check spark plugs
(adjusting gap to 0.8-0.9 mm), inspect breather and fuel line, check low
pressure fuel filter, inspect sacrificial anodes, verify thermostat
operation, check propeller nut and cotter pin, and check battery
condition on electric start models.
Every 200 hours, in addition to the 100-hour checks, the engine requires
replacement of the oil filter, inspection and adjustment of valve lash,
inspection of the timing belt, checking and adjusting idle speed, and
inspecting the water pump and its impeller.
Every 300 hours, the spark plugs should be replaced with NGK MR6K-9, and
the water pump impeller must be replaced to prevent cooling system
failure. Every 400 hours, the timing belt should be replaced and the
fuel filter should be replaced. Engine oil capacity is 1.00 liter.
Gearcase capacity is 0.25 liters. Spark plug gap is 0.8-0.9 mm. Valve
lash is 0.16-0.20 mm for both intake and exhaust valves. Ignition timing
is 5-20 degrees BTDC. Recommended oil is Suzuki Marine 4-Stroke Engine
Oil SAE 10W-40 Semi-Synthetic.
Cylinder head bolt - 15 Nm first step, 30 Nm final step (11 lb-ft first,
21.7 lb-ft final)
Cylinder head cover bolt - 10 Nm (7.2 lb-ft)
Conrod cap bolt - 10 Nm (7.2 lb-ft)
Flywheel nut - 90 Nm (65.0 lb-ft)
Camshaft pulley bolt - 10 Nm (7.2 lb-ft)
Timing pulley nut - 50 Nm (36.0 lb-ft)
Side cover screw - 5 Nm (3.6 lb-ft)
Spark plug - 10-12 Nm (7.5-9.0 lb-ft)
Tiller handle bolt - 23 Nm (16.5 lb-ft)
Tiller handle bracket bolt - 23 Nm (16.5 lb-ft)
Steering friction adjuster nut - 9 Nm (6.5 lb-ft)
Throttle grip screw - 3 Nm (2.1 lb-ft)
Driveshaft housing bolt - 23 Nm (16.5 lb-ft)
Shallow drive arm bolt - 25 Nm (18.0 lb-ft)
Clamp bracket shaft nut - 43 Nm (31.0 lb-ft)
Propeller nut - 18 Nm (13.0 lb-ft)
Gearcase bolt - 17 Nm (12.3 lb-ft)
Water pump case nut - 6 Nm (4.3 lb-ft)
Bearing housing bolt - 8 Nm (5.8 lb-ft)
Power unit mounting bolt - 23 Nm (16.5 lb-ft)
Intake manifold - 23 Nm (16.5 lb-ft)
Throttle body - 11 Nm (8.0 lb-ft)
Low pressure fuel pump bolt - 10 Nm (7.2 lb-ft)
Fuel delivery pipe bolt - 11 Nm (8.0 lb-ft)
Starter motor mounting bolt - 23 Nm (16.5 lb-ft)
Oil filter cover bolts (6mm) - 8-11.5 Nm (6-8.5 lb-ft)
The Suzuki DF20AS is engineered for a wide variety of watercraft
applications requiring short shaft configurations. Its compact size,
light weight under 50 kg making it easily transportable, and advanced
features make it an ideal primary power source for small fishing boats,
aluminum boats, jon boats, skiffs, dinghies, and inflatable craft
including RIBs for coastal waters or lakes.
It is particularly well-suited for boats with transom heights of 15
inches, providing proper engine mounting and performance. The engine is
also a popular and dependable choice as an auxiliary motor for larger
fishing boats or sailboats, providing reliable power and
maneuverability. With its 20 hp output, advanced EFI technology
featuring Lean Burn fuel efficiency, and lightweight construction, it is
well-suited for recreational boaters and anglers seeking an efficient,
quiet, and reliable outboard for various water conditions.
The engine is saltwater rated and suitable for use in both freshwater
and saltwater environments when properly maintained, featuring Suzuki's
special anti-corrosion treatment to protect against corrosive elements
such as saltwater. The DF20AS meets current emission and noise
regulations.
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