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Evinrude 120 V4 Specifications
| Engine Model: Evinrude 120 V4 |
| Engine Type: 2-stroke 4-cylinder gasoline outboard engine |
| Total Displacement: 110 cu.in (1.8 L) |
| Rated Engine Power: 120 Hp (89 kW) at 5500 rpm |
| Fuel System: Carburetors or electronic fuel injection (EFI) |
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| General Technical Data |
The Evinrude 120 V4 is a two-stroke outboard
engine produced by Outboard Marine Corporation (OMC) and later
Bombardier Recreational Products (BRP). Representing a major step in
two-stroke evolution, this powerhead utilizes a 90-degree V4
configuration and a loop-charged scavenging system. This design
supersedes the older crossflow principle, delivering improved fuel
efficiency and smoother power delivery.
Its production run, particularly from 1995 onward, is characterized by a
mature and stable design with excellent parts commonality. The engine
includes integrated Power Tilt and Trim as standard equipment. Known for
robust mid-range torque and proven durability, the Evinrude 120 V4 is a
respected powerplant found on a vast array of recreational and light
commercial vessels from the late 1980s through the 2000s.
Engine Designation: Evinrude 120 V4 (Loop-Charged)
Engine Type: Two-stroke, loop-charged scavenging
Cylinder Arrangement: 90-degree V4
Bore: 3.500 inches (88.9 mm)
Stroke: 2.865 inches (72.8 mm)
Displacement: 110 cubic inches (1.8 liters)
Compression Ratio: 6.0:1
Rated Power: 120 Hp (89 kW) at 5,500 RPM
Full Throttle Operating Range: 5,000 to 6,000 RPM
Ignition System: Electronic Capacitor Discharge Ignition (CDI) with
electronic timing advance. Solid-state power pack and trigger assembly.
Starting System: 12-volt electric starter motor with solenoid.
Charging System: 35-amp belt-driven alternator.
Direction of Rotation: Standard right-hand rotation. Counter-rotation
models (identified by "R" suffix) are available for dual installations.
Gear Ratio: 1.86:1
Gear Shift: Forward, neutral, reverse via hydraulic-mechanical
actuation.
Exhaust System: Through-the-propeller-hub underwater exhaust.
| Cylinder Block |
The cylinder block is a rigid aluminum alloy casting configured in a 90-degree V4 layout. This design offers superior primary balance compared to a 55-degree or 60-degree V4. The block incorporates pressed-in cast iron cylinder liners for durability.
It houses a forged steel crankshaft supported by five main bearings. The 90-degree design allows for a compact overall width while maintaining effective cooling passages between cylinders. The block casting includes integral mounting bosses for the intake manifold, oil injection pump, and external components.
| Cylinder Head and Valves |
As a loop-charged two-stroke engine, it operates without traditional poppet valves. Gas exchange is controlled by piston-port timing. Each cylinder is fitted with a separate aluminum alloy cylinder head, sealed with a metal gasket.
The combustion chamber is a compact, machined cavity designed to promote efficient swirl and combustion of the fuel-air charge. The loop-charging process uses intake and exhaust ports located on the same side of the cylinder, with a shaped piston crown and combustion chamber to direct gases in a loop pattern for superior scavenging efficiency.
| Fuel System |
The fuel system on later production models is a multi-point electronic fuel injection (EFI) system or a carbureted system, depending on model year. Carbureted versions employ four fixed-jet, downdraft carburetors (one per cylinder) fed by a diaphragm fuel pump.
EFI models feature an electric fuel pump, a throttle body assembly, and four electronic fuel injectors mounted in the intake manifold. For carbureted models, the recommended fuel is 87 octane (R+M)/2 unleaded gasoline. All models use an oil-injection system.
| Lubrication System |
The engine is equipped with the Variable Ratio Oiling (VRO2) or the later Ficht Ram Injection oil delivery system. This is an automatic, demand-based system. A dedicated oil pump, driven by the crankshaft, meters lubricant directly into the intake manifold.
The oil delivery rate is electronically modulated based on engine RPM and throttle position, varying the oil-to-gas ratio from approximately 150:1 at idle to 50:1 at wide-open throttle. A separate oil tank, low-oil sensor, and warning system are integral components.
| Cooling System |
The cooling system is a positive-pressure, raw-water type. A rubber impeller water pump, located in the gearcase, draws ambient water through the intake screens. Coolant water is forced up the driveshaft housing into the engine.
Flow is directed through the cylinder block, cylinder heads, and exhaust manifolds. A thermostat regulates engine temperature, maintaining operation between 140-150 F (60-66 C). A visual tell-tale stream confirms pump operation. The system includes a pressure-controlled relief valve for over-pressure conditions.
| Other Systems |
Electrical System: 12-volt negative ground. Includes a 35-amp alternator, a solid-state voltage regulator, and a CDI ignition module. Wiring harness incorporates weather-sealed connectors. Power Trim and Tilt: A hydraulic system is standard. It consists of an electric motor-driven hydraulic pump, fluid reservoir, and two or three hydraulic trim/tilt cylinders mounted on the stern bracket.
Exhaust System: Tuned exhaust passages within the mid-section. Exhaust gases are cooled and silenced by water discharge before being expelled underwater via the propeller hub. Gearcase (Lower Unit): A high-strength aluminum alloy casting.
Houses a single-piece driveshaft, stainless steel prop shaft, forward/neutral/reverse gears, and the water pump. Lubricant capacity is 22 fluid ounces (0.65 liters) of Evinrude/Johnson Gearcase Lube or equivalent. Propeller Shaft: 13-spline configuration, accommodating a wide range of propeller options.
| Dimensions and Weight |
Dry Weight (Approximate): 365 lbs (166 kg). This weight includes the
standard integrated Power Trim and Tilt system. Shaft Lengths Available:
20 inches (508 mm) and 25 inches (635 mm).
Overall Profile: The 90-degree V4 design is compact in width. Height and
length are proportional to shaft length selection.
| Maintenance Data |
Spark Plug: Champion QL77JC4 or equivalent. Gap: 0.040 inches (1.0 mm).
Fuel Filter: Inline canister-type element. Replace annually.
Water Pump Impeller: Service every two years or 300 operating hours.
Gearcase Lubricant: Drain and refill annually. Inspect lubricant for
metal particles or water contamination (milky appearance).
Oil Injection System: Never allow the oil tank to run dry. Purge the
system after any component service or hose replacement.
Link and Sync (Carbureted Models): Mandatory procedure to synchronize
carburetor throttle plates with ignition timing advance.
Anode Inspection: Inspect and replace sacrificial zinc anodes as
required to prevent galvanic corrosion.
| Tightening Torques |
Cylinder Head Nuts: 20-22 lb-ft (27-30 Nm). Follow the specified
crisscross sequence.
Spark Plugs: 15 lb-ft (20 Nm).
Flywheel Nut: 90-105 lb-ft (122-142 Nm). Requires crankshaft locking
tool.
Main Bearing Cap Bolts: 22-24 lb-ft (30-33 Nm).
Connecting Rod Cap Nuts: 17-19 lb-ft (23-26 Nm). Use new locking inserts
or cotter pins as specified.
Gearcase Drain/Fill Screws: 60-80 lb-in (6.8-9.0 Nm).
Propeller Nut: 55 lb-ft (75 Nm). Secure with cotter pin.
Engine Mount (Swivel Bracket) Nuts: 55 lb-ft (75 Nm).
| Boat Applications |
The Evinrude 120 V4, with its 90-degree loop-charged design, served as a primary and secondary power source for a broad spectrum of boats. Primary Power: Suitable as a single installation on boats from 15 feet to 20 feet in length. Twin Installation: Commonly used in twin configurations on boats from 18 feet to 25 feet for enhanced performance and redundancy.
Boat Types: Deep-V hull fishing boats, center consoles, aluminum fishing boats, family bowriders, and pontoon boats. Common Hull Brands: Found on models from Crestliner, Lund, Triton, Starcraft, Bayliner, and numerous other manufacturers during its production era. Its 13-spline propeller shaft ensures wide propeller availability for diverse applications.
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