Yamaha F70AETL Specifications
| Engine Model: Yamaha F70AETL |
| Engine Type: 4-stroke inline 4-cylinder SOHC 16-valve gasoline outboard engine |
| Total Displacement: 60.8 cu.in (996 cc) |
| Rated Engine Power: 70 Hp (51.5 kW) at 5800 rpm |
| Fuel System: Electronic Fuel Injection (EFI) |
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The Yamaha F70AETL is a 70-horsepower,
four-stroke, in-line four-cylinder outboard engine, representing a
pinnacle of power-to-weight engineering in Yamaha's mid-range lineup.
This model is specifically configured for remote control operation and
is equipped with electric starting and a hydraulic power trim and tilt
system, offering boaters a sophisticated, powerful, and exceptionally
smooth experience.
Built on an advanced 996cc platform, the F70AETL is renowned as the
lightest 70hp four-stroke outboard in its class, celebrated for its
quiet operation, outstanding fuel efficiency, and the seamless response
of its Electronic Fuel Injection system, making it a versatile and
dependable choice for a wide array of boats including RIBs, aluminum
fishing boats, and pontoons.
The Yamaha F70AETL is constructed around a refined and efficient
powerhead. It features a 4-stroke, SOHC, in-line 4-cylinder, 16-valve
engine configuration. The engine displacement is precisely 996 cc (60.8
cu in), achieved through a bore and stroke of 65.0 mm x 75.0 mm (2.56 in
x 2.95 in).
This powerhead produces a maximum prop shaft output of 51.5 kW (70 hp)
at 5,800 rpm. The engine is engineered to operate within a full throttle
operating range of 5,300 to 6,300 rpm, with a specified engine idle
speed of 700-800 rpm. The compression ratio is stated as 9.4:1.
The power unit of the F70AETL is engineered for durability, efficiency,
and smooth power delivery. The long-stroke design contributes to high
power output and remarkably smooth operation with low noise and
vibration levels. The advanced powerhead features a single overhead
camshaft (SOHC) with four valves per cylinder, maximizing power and
efficiency.
Total intake valve area is increased significantly, while the pistons
and valves are lighter, giving it substantially more
horsepower-per-litre of engine displacement than competitors. The
overhead camshaft design efficiently exchanges intake and exhaust gases
for responsive power and fuel efficiency. The valve train requires
periodic adjustment, with specified valve clearances of 0.15-0.25 mm
(0.006-0.010 in) for the intake valves and 0.25-0.35 mm (0.010-0.014 in)
for the exhaust valves.
The F70AETL features Yamaha's advanced Electronic Fuel Injection (EFI)
system, which precisely meters fuel for optimal combustion under all
conditions. Four individual compact electronic fuel injectors deliver
the exact amount of fuel needed for optimum performance and economy,
with their location just above the intake valves enhancing fuel
atomization for more efficient combustion.
Managed by an Engine Control Module (ECM) microcomputer via input from
an array of on-engine sensors, this system ensures cleaner performance,
impressive fuel economy, and seamless throttle response.
Air entering the engine is routed through a single throttle valve to
ensure precise air metering, then enters each cylinder through
individual long, pulse-tuned intake tracks for maximum density and
power. The recommended fuel is regular unleaded gasoline with a minimum
octane rating of 87. The engine is supplied with fuel from a separate
tank with a capacity of 25.0 L (6.6 US gal).
The lubrication system is a wet sump type, meaning the engine oil is
stored in a sump within the engine. The recommended engine oil is
high-quality 4-stroke outboard motor oil, such as Yamalube 4-M FC-W
10W-30, meeting API SE, SF, SG, SH, SJ, or SL service classifications.
The engine oil capacity with filter replacement is 2.1 L (2.2 US qt),
while the capacity during a change without filter replacement is 1.9 L
(2.0 US qt).
The cooling system is raw-water with thermostatic control, drawing water
from the body of water to cool the engine. Exhaust gases are expelled
through the propeller boss for efficient underwater exhaust and noise
reduction. A large anti-splash plate on the front of the lower
mid-section helps keep water from splashing up between the outboard and
the boat for a dryer ride.
The ignition system is a TCI (Transistor Controlled Ignition)
microcomputer unit, providing precise spark timing for reliable starting
and efficient power across the RPM range. The system includes the Prime
Start feature for effortless cold starts, similar to starting a car.
The specified spark plugs are NGK LKR7E, with a required gap of 0.8-0.9
mm (0.031-0.035 in). The charging system incorporates a high-output
alternator of 12V - 15A or 17A with a built-in rectifier/regulator to
maintain battery charge.
| Mid Section and Lower Unit |
The lower unit is engineered for strength and efficiency. It uses a
spiral bevel gear with a reduction gear ratio of 2.33:1 (28/12) , which
provides outstanding hole shot and acceleration. Specially hardened
pinion, forward, and reverse gears increase durability.
The gear shift positions are the standard Forward-Neutral-Reverse
(F-N-R), engaged via a positive-action dog clutch. The propeller shaft
utilizes a spline drive system, and the propeller direction, when viewed
from the rear, is clockwise. The correct lubricant for the lower unit is
hypoid gear oil meeting API GL-4 SAE 90 specifications, with a gear oil
capacity of 0.67 L (0.70 US qt).
This outboard is equipped with a hydraulic power trim and tilt system,
allowing for effortless adjustment of the engine angle with the touch of
a button. The wide-range power trim and tilt (WRPTT) system allows
adjustment of the trim angle from -4 degrees to +16 degrees , enabling
the operator to fine-tune the boat's attitude for optimal performance,
fuel efficiency, and ride quality under various load and water
conditions.
Negative trim angles improve acceleration and help achieve planing
quickly. For shallow water operation, the system provides a standard
shallow water drive feature, allowing the engine to be operated at a
tilted angle for safe navigation. The maximum tilt-up angle is 65
degrees. The steering angle is 40 degrees to both port and starboard.
The Yamaha F70AETL is equipped with a standard aluminum three-blade
propeller with a diameter of 13-1/2 inches. Authorized Yamaha dealers
can recommend the correct propeller based on boat hull, load, and
intended use to ensure the engine operates within its recommended
full-throttle RPM range of 5,300-6,300 rpm.
The Yamaha F70AETL is designed as a long shaft model. The overall length
is 698 mm (27.5 in) and the overall width is 386 mm (15.2 in). The
overall height is 1,476 mm (58.1 in) with a recommended transom height
of 527-534 mm (20.7-21.0 in). The dry weight for this model is 119 kg
(262 lb).
Regular maintenance is essential for the longevity of the F70AETL. The
engine oil and oil filter should be changed according to the
manufacturer's schedule. The gear oil in the lower unit should be
checked regularly for the presence of water or metal particles and
changed annually or every 100 hours. The water pump impeller is a wear
item that should be inspected and replaced periodically, every 1-2 years
or if there are signs of reduced cooling water flow, to prevent
overheating.
The spark plugs should be removed, inspected, cleaned, and the gap
adjusted annually, and replaced as needed. Valve clearance inspection
and adjustment should be performed at recommended intervals.
All moving parts, such as steering linkages and tilt tube, require
regular greasing with water-resistant marine grease to prevent corrosion
and ensure smooth operation. A large, on-engine water-separating fuel
filter with a water sensor helps separate water and contaminants from
the fuel before they can reach the injectors. Modern warning systems
monitor oil pressure, temperature, and other key parameters, activating
audible and visual alerts if malfunctions occur.
Spark plug: 17 Nm (12.5 lb-ft)
Propeller nut: 34 Nm (25 lb-ft)
Oil drain plug: 27 Nm (20 lb-ft)
Oil filter: 18 Nm (13.5 lb-ft)
The Yamaha F70AETL is a versatile power source ideally suited for a wide
range of mid-sized watercraft. Its 70-horsepower output, combined with
the convenience of electric start, EFI, and power trim and tilt, makes
it a perfect match for aluminum fishing boats, center consoles, bay
boats, and utility boats commonly used on inland lakes and coastal
waters. It is exceptionally popular as power for rigid inflatable boats
(RIBs) up to approximately 5.5 meters, where its light weight and power
provide excellent performance.
The engine is also ideal for pontoon boats, where the anti-splash plate
proves beneficial, and for towing watersports enthusiasts thanks to its
clean and quiet four-stroke operation. Features such as precise trolling
control, adjustable in 50-rpm increments from 620-900 rpm via optional
Command Link gauges or the multifunction tiller handle, make it
excellent for walleye trolling and other slow-speed applications.
Compatibility with Yamaha's Digital Network Gauges delivers precise
control and monitoring capabilities.
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