Suzuki DF90A Specifications
| Engine Model: Suzuki DF90A |
| Engine Type: 4-stroke inline 4-cylinder DOHC 16-valve gasoline outboard engine |
| Total Displacement: 91.6 cu.in (1.5 L) |
| Rated Engine Power: 90 Hp (66.2 kW) at 6000 rpm |
| Fuel System: Multi point sequential electronic fuel injection |
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The Suzuki DF90A is a technologically advanced
90 Hp outboard that redefines expectations in the mid-range category. It
is the lightest, most compact, and most fuel-efficient outboard in its
class. Its most distinguishing feature is the largest reduction gear
ratio in its class at 2.59:1, which translates into powerful torque for
quick acceleration and the ability to turn large diameter propellers
with high propulsive efficiency, maintaining propeller rotation even
with a larger load.
The offset driveshaft design positions the powerhead closer to the
front, moving the outboard's center of gravity forward for improved
weight distribution, reduced vibration, more stable steering
performance, and a more compact overall footprint. The Lean Burn Control
System optimizes the air-fuel mixture based on operating conditions,
providing significant improvements in fuel economy across all speed
ranges, especially at cruising speed.
With features like the Suzuki Keyless Start System with immobilizer,
tilt limit protection, and the optional Troll Mode System, the DF90A is
engineered to provide a premium and worry-free boating experience.
Engine Model: Suzuki DF90A
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: 75.0 mm x 85.0 mm (2.95 in x 3.35 in)
Piston Displacement: 1502 cc (91.6 cu. in)
Maximum Output: 66.2 kW (90 Hp)
Full Throttle Operating Range: 5500-6300 rpm
Idle Speed: 600 ± 50 rpm
Fuel Delivery System: Multi-Point Sequential Electronic Fuel Injection
Alternator: 12V 27A
Steering: Remote (Tiller Kit Optional on TH models)
Trim Method: Power Trim and Tilt
Gear Ratio: 2.59:1 (2-stage gear reduction)
Gear Shift: F-N-R (Forward-Neutral-Reverse)
Exhaust: Through Prop Hub Exhaust
Propeller Selection: 13"-25" pitch range, various 3-blade aluminum
propellers available
Starting System: Electric
Ignition System: Full-transistorized ignition
Engine Lubrication: Wet sump by trochoid pump
Engine Oil Capacity: 4.3 L (4.5 qt) with filter change; 4.0 L without
filter
Gear Oil Capacity: 0.85 L (28.7/30.0 US/Imp. oz.)
Compression Ratio: 9.5:1
Spark Plug: NGK DCPR6E
Spark Plug Gap: Standard: 0.8-0.9 mm (0.031-0.035 in)
Fuel Type: Alcohol-free unleaded gasoline
Minimum Fuel Octane Rating: 87 (R+M/2 method) or 91 (Research method)
The DF90A is built upon a robust inline four-cylinder block with a
displacement of 1502 cc, utilizing a bore and stroke of 75.0 mm and 85.0
mm respectively. The powerhead features a DOHC 16-valve configuration
for optimal airflow and combustion efficiency, with four valves per
cylinder and a "V" type valve configuration. The powerhead is designed
with a left-hand rotation to maintain conventional right-hand propeller
shaft output through the offset driveshaft system.
A key feature is the self-adjusting oil-bathed timing chain, which runs
in an oil bath so it never needs lubrication and is equipped with an
automatic hydraulic tensioner that keeps it properly adjusted at all
times. This design offers higher durability compared to belt systems and
is completely maintenance-free.
The offset driveshaft positions the crankshaft in front of the
driveshaft, moving the outboard's center of gravity forward. This
results in reduced vibration, a more compact engine footprint, more
stable steering performance, and keeps the overall motor's weight closer
to the boat transom and therefore closer to the boat's center of
gravity.
Cylinder bore std: 75.000-75.020 mm (2.9598-2.9535 in)
Piston skirt diameter std: 74.970-74.990 mm (2.9516-2.9524 in)
Piston to cylinder clearance std: 0.020-0.040 mm (0.0008-0.0016 in)
Piston ring end gap std: 0.30-0.45 mm (0.0118-0.0177 in)
Valve diameter (Intake): 27.5 mm (1.08 in)
Valve diameter (Exhaust): 22.9 mm (0.90 in)
The DF90A's fuel system is centered around the Suzuki Lean Burn Control
System, an intelligent technology that supplies the right fuel and air
mixture depending on navigation conditions. By predicting fuel needs
based on operating conditions and delivering an optimized air-fuel
mixture, this system provides significant improvements in fuel economy
across all speed ranges, especially at cruising speed, reducing fuel
costs and enhancing efficiency.
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
Suzuki Easy Start System allows the operator to simply turn and release
the key, with the starter remaining engaged until the engine starts. An
optional Troll Mode System is available for precise low-speed control in
trolling applications, allowing engine speed adjustments in 50 rpm
increments from idle up to 1200 rpm.
The DF90A employs a wet sump lubrication system with a trochoid pump to
ensure consistent pressurized oil delivery to all critical engine
components. The engine has an oil capacity of 4.3 liters with filter
change.
Recommended engine oil is high-quality 4-stroke motor oil meeting NMMA
FC-W certification or API classification SG, SH, SJ, SL, SM, with
viscosity SAE 10W-40 recommended for most conditions. An oil change
reminder system helps track service intervals.
Engine temperature is managed by a reliable direct 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 thermostat should be inspected periodically according to the
maintenance schedule. The cooling system is designed for efficient heat
dissipation under all operating conditions.
| 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, 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 with tremendous power, resulting in quick acceleration, high
propulsive efficiency, and the ability to maintain propeller rotation
even with a larger load.
The lower gear case utilizes a streamlined hydrodynamic design that
reduces drag as the lower unit moves through the water, contributing to
faster acceleration and increased speed. Drive line impact protection is
provided by a spline drive rubber hub. Exhaust gases are channeled
through the propeller hub for quieter operation.
The Power Trim and Tilt (PTT) system provides hydraulic control over the
outboard's angle, allowing the operator to adjust boat trim for optimal
performance, fuel efficiency, and ride comfort. The trim angle range is
0-20 degrees (-6 to 14 degrees), and the maximum tilt angle is 75
degrees (-6 to 69 degrees).
The Tilt Limit System incorporates a user-adjustable, step-free
continuous tilt limit switch that prevents the outboard from tilting
beyond a predetermined point, protecting both the engine and the boat
from damage caused by excessive tilting and allowing installation on
almost any boat. A manual release valve is provided for emergency
operation.
The DF90A is designed to work with a comprehensive range of propellers
to match various boat types and load conditions. The recommended full
throttle speed range is 5500-6300 rpm. Installing a propeller with pitch
either too high or too low will cause incorrect maximum engine speed,
which may result in severe damage to the motor. All propellers are
three-blade type.
Available propeller options include various
diameters and pitches:
3 x 14 x 13
3 x 13-7/8 x 15
3 x 13-3/4 x 17
3 x 13-3/4 x 19
3 x 13-3/4 x 21
3 x 13-3/4 x 23
3 x 13-1/2 x 15
3 x 14 x 17
3 x 14 x 19
3 x 14 x 21
3 x 14 x 23
Transom Height (Long Shaft - L): 508 mm (20 in)
Transom Height (Extra Long Shaft - X): 635 mm (25 in)
Overall Length (front to back): 724 mm (28.5 in)
Overall Width (side to side): 459 mm (18.1 in)
Overall Height (Long Shaft): 1480 mm (58.2 in)
Overall Height (Extra Long Shaft): 1607 mm (63.3 in)
Dry Weight (Long Shaft): 156-160 kg (343-352 lbs) depending on
configuration
Dry Weight (Extra Long Shaft): 160-164 kg (353-361 lbs) depending on
configuration
Engine Mounting: Shear mount
Initial Service: Perform at 20 hours or 1 month
Engine Oil: Replace every 100 hours or 12 months
Engine Oil Filter: Replace at initial 20 hours, then every 200 hours or
12 months
Gear Oil: Replace every 100 hours or 12 months
Spark Plugs: Inspect every 100 hours or 12 months
Valve Clearance: Inspect every 300 hours or 36 months
Water Pump Impeller: Inspect every 200 hours; replace as needed
Low Pressure Fuel Filter: Inspect every 100 hours; replace every 2-3
years
High Pressure Fuel Filter: Replace periodically
Anodes (External): Inspect every 100 hours or 12 months
Propeller Nut and Cotter Pin: Inspect at each interval
Bolts and Nuts: Check tightness at each interval
Engine Oil Capacity: 4.3 L (4.5 qt) with filter change; 4.0 L without
filter
Recommended Oil: 4-stroke motor oil, NMMA FC-W oil, or API SG, SH, SJ,
SL, SM
Oil Viscosity SAE 10W-40
Gear Oil Capacity: 0.85 L (28.7/30.0 US/Imp. oz.)
Recommended Oil: Suzuki Outboard Motor Gear Oil or API GL5, SAE 90
Hypoid gear oil
Spark Plugs: NGK DCPR6E (resistor type only)
Spark Plug Gap: 0.8-0.9 mm (0.031-0.035 in)
Cylinder head cover bolt: 11 Nm (8.0 lb-ft)
Cylinder head bolt (8 mm): 23 Nm (16.6 lb-ft)
Cylinder head bolt (10 mm): 70 Nm (51.0 lb-ft)
Crankcase bolt (Outside): 25 Nm (18.0 lb-ft)
Crankcase bolt (Inside): 52 Nm (37.5 lb-ft)
Conrod cap bolt: 47 Nm (40.0 lb-ft)
Camshaft housing bolt: 11 Nm (8.0 lb-ft)
Oil pump bolt: 15 Nm (11.0 lb-ft)
Chain tensioner adjuster bolt: 11 Nm (8.0 lb-ft)
Timing chain guide bolt: 23 Nm (16.6 lb-ft)
Intake manifold bolt / nut: 23 Nm (16.5 lb-ft)
Throttle body bolt: 10 Nm (7.2 lb-ft)
Fuel delivery pipe bolt: 23 Nm (16.5 lb-ft)
Low pressure fuel pump bolt: 10 Nm (7.0 lb-ft)
Flywheel bolt: 196 Nm (142.0 lb-ft)
Starter motor mounting bolt: 23 Nm (16.6 lb-ft)
Oil pressure switch: 13 Nm (9.5 lb-ft)
Thermostat cover bolt: 10 Nm (7.0 lb-ft)
Water pump case bolt: 17 Nm (12.3 lb-ft)
Power unit mounting bolt (8 mm): 23 Nm (16.5 lb-ft)
Power unit mounting bolt (10 mm): 50 Nm (36.0 lb-ft)
Driveshaft housing bolt: 50 Nm (36.0 lb-ft)
Lower mount bolt: 60 Nm (43.4 lb-ft)
Clamp bracket shaft nut: 43 Nm (31.0 lb-ft)
Cylinder lower shaft bolt: 50 Nm (36.0 lb-ft)
Propeller shaft bearing housing bolt: 23 Nm (16.6 lb-ft)
Propeller nut: 55 Nm (40.0 lb-ft)
Engine oil filter: 14 Nm (10.0 lb-ft)
Engine oil drain plug: 13 Nm (9.5 lb-ft)
Fishing Boats: An excellent primary power source for small to mid-sized
fishing boats, bay boats, and side consoles, offering the torque needed
for quick planing and efficient trolling with the optional Troll Mode
System. Family and Recreational Boats: Powers family runabouts,
bowriders, and sport boats used for cruising, waterskiing, and tubing
activities.
Pontoon Boats: A popular choice for powering pontoon boats, where its
quiet, fuel-efficient operation enhances the leisurely cruising
experience. Rigid Inflatable Boats (RIBs): Suitable for RIBs and small
center consoles where lightweight power is advantageous. Commercial and
Work Applications: Its robust construction, fuel efficiency, and
reliability make it a dependable choice for various light-duty
commercial applications, with Suzuki outboards trusted by operators such
as Sea Start and Solent RIB Charter.
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