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Yamaha F50HETL Specifications
| Engine Model: Yamaha F50HETL |
| Engine Type: 4-stroke inline 4-cylinder SOHC 8-valve gasoline outboard engine |
| Total Displacement: 60.8 cu.in (996 cc) |
| Rated Engine Power: 50 Hp (36.8 kW) at 5500 rpm |
| Fuel System: Electronic Fuel Injection (EFI) |
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| General Technical Data |
The Yamaha F50HETL is a 50-horsepower,
four-stroke, in-line four-cylinder outboard engine, representing a
pinnacle of refinement and technology 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 a advanced 996cc platform, the F50HETL is renowned 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 mid-sized boats.
The Yamaha F50HETL is constructed around a refined and efficient
powerhead. It features a 4-stroke, SOHC, in-line 4-cylinder, 8-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 36.8 kW (50 hp)
at 5,500 rpm. The engine is engineered to operate within a full throttle
operating range of 5,000 to 6,000 rpm, with a specified engine idle
speed of 700-800 rpm. The compression ratio is stated as 9.5:1.
| Powerhead |
The power unit of the F50HETL is engineered for durability, efficiency, and smooth power delivery. The engine's design incorporates a long intake manifold and increased piston stroke, contributing to a broad, flat torque curve and impressive acceleration.
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.
| Fuel System |
The F50HETL features Yamaha's advanced Electronic Fuel Injection (EFI) system, which precisely meters fuel for optimal combustion under all conditions. Managed by a microcomputer receiving data from six different engine sensors, this system ensures cleaner performance, impressive fuel economy, and seamless throttle response.
The recommended fuel is regular unleaded gasoline with a minimum octane rating of 86. The engine is supplied with fuel from a separate tank, with a capacity of 25.0 L (6.6 US gal).
| Lubrication System |
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, in SAE 10W-30 or 10W-40 viscosities, meeting API SE, SF, SG, SH, SJ, or SL service classifications.
The engine oil capacity, including the filter, 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).
| Cooling System |
The cooling system is raw-water, thermostatically controlled, drawing water from the body of water to cool the engine. A freshwater flushing device is integrated for easy maintenance. Exhaust gases are expelled through the propeller boss for efficient underwater exhaust and noise reduction.
| Ignition System |
The ignition system is a TCI (Transistor Controlled Ignition) 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 DPR6EB-9, 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 - 16A with a built-in rectifier/regulator to maintain battery charge for the electric start and other electrical accessories.
| 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 1.85:1 (24/13). 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 0.43 L (0.45 US qt).
| Trim and Tilt System |
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 trim angle can be adjusted through a wide range, from -4
degrees (tuck/under) to +20 degrees (trim out) , enabling the operator
to fine-tune the boat's attitude for optimal performance, fuel
efficiency, and ride quality under various load and water conditions.
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, with a maximum tilt-up angle for trailering
of 69 degrees. The steering angle is 40 degrees to both port and
starboard.
| Propeller Information |
The Yamaha F50HETL is compatible with a wide range of aluminum and stainless steel propellers to match various boat types and applications. While specific propeller sizes for this model are not detailed in the provided search results, 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 5,000-6,000 rpm.
| Dimensions and Weight |
The Yamaha F50HETL 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 1,435 mm (56.5 in) with a recommended transom height of 527 mm (20.7 in). The dry weight for this model is 113-114 kg (249-251 lb).
| Maintenance Data |
Regular maintenance is essential for the longevity of the F50HETL. The
engine oil and oil filter should be changed according to the
manufacturer's schedule, with the filter change torque specified at 18
Nm (13.5 lb-ft).
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.
| Tightening Torques |
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)
| Boat Applications |
The Yamaha F50HETL is a versatile power source ideally suited for a wide
range of mid-sized watercraft up to approximately 5 meters in length.
Its 50-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 also a popular choice for rigid inflatable boats (RIBs) and as a
dependable primary motor for small pontoons and deck boats. The
four-stroke technology provides exceptionally clean and quiet operation,
making it ideal for towing watersports enthusiasts. Yamaha's advanced
corrosion protection and the availability of options like the Y-COP
engine immobilizer ensure long-term reliability and security.
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