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Mercury 400 L6 Verado Specifications
| Engine Model: Mercury Verado 400 L6 |
| Engine Type: 4-stroke 6-cylinder DOHC 24-valve supercharged gasoline outboard engine |
| Total Displacement: 158.5 cu.in (2.6 L) |
| Rated Engine Power: 400 Hp (298 kW) at 6800 rpm |
| Fuel System: Sequential multi-point electronic fuel injection (EFI) |
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| General Technical Data |
The Mercury Verado 400 L6 is defined by its
supercharged power delivery and exceptional power-to-weight ratio. The
heart of this engine is a 2.6-liter inline-six, an inherently balanced
architecture, that is force-fed by a sophisticated supercharger system
with charge air cooling. This combination generates immense,
instantaneous torque that translates into stunning real-world
performance.
Mercury states the 400hp Verado accelerates from 0 to 20 mph eight
seconds quicker than a competitor's 350hp engine and achieves a top
speed four miles per hour faster. This formidable power is delivered
with a quietness and civility that is remarkable, thanks to the Advanced
MidSection (AMS) which isolates the powerhead and virtually eliminates
vibration transmission to the hull.
With a dry weight of just 668 lbs, it holds a significant weight
advantage over competitors, being nearly 300 lbs lighter than a leading
425hp outboard. The 400 L6 is fully integrated with Mercury's SmartCraft
digital technology, including Digital Throttle and Shift (DTS) and
electro-hydraulic power steering, providing precise, fingertip control.
For boat owners who demand the ultimate in supercharged performance
combined with lightweight efficiency, the Verado 400 L6 represents a
benchmark achievement.
Engine Type: Inline 6-cylinder (L6), four-stroke, supercharged.
Valvetrain: Dual Overhead Camshafts (DOHC) with 24 valves.
Displacement: 2.6 Liters (158.5 Cubic Inches).
Bore and Stroke: 82 mm by 82 mm (3.23 inches by 3.23 inches).
Power Output: 400 Hp at the propeller shaft (298 kW).
Full Throttle Operating Range: 6200-6800 RPM.
Idle RPM (in neutral): 600 RPM.
Air Induction: Supercharged system with a Cold Air Intake, charge air
cooling, and electronic boost pressure control to manage power delivery
and maintain air density for maximum combustion efficiency.
Fuel Induction System: Sequential multi-port electronic fuel injection
(EFI).
Ignition System: SmartCraft Digital Inductive ignition.
Alternator Output: A high-output 150-amp alternator produces 1890 W,
providing substantial electrical power for modern onboard electronics
and battery charging.
Recommended Fuel: For maximum performance, unleaded 95 RON is
recommended, with a minimum of 93 RON. For North American markets, 91
Octane (R+M)/2 is recommended.
Recommended Oil: Mercury FourStroke 25W-40 Marine Oil.
Engine Oil Capacity: 7.4 US quarts (7.0 Liters).
Engine Protection: The SmartCraft Engine Guardian system monitors
critical sensors and can automatically reduce power to prevent damage
from adverse operating conditions.
Starting System: Electric Start with SmartStart Protection, which
prevents starter motor engagement if the engine is already running.
Steering: Electro-hydraulic power steering, compatible with Joystick
Piloting for Outboards.
Controls: Mercury SmartCraft Digital Throttle and Shift (DTS).
Emissions Compliance: CARB 2-star rating.
Battery Requirements: 800 minimum marine cranking A (MCA) with a minimum
reserve capacity of 135 minutes (RC25 rating).
| Powerhead |
The L6 engine's architecture is central to its performance character and
legendary smoothness.
Cylinder Block: The engine is built on a robust 2.6-liter inline
6-cylinder block. This configuration is inherently balanced, eliminating
many of the primary vibrations found in other engine types. The
deep-skirt block design provides a stiff foundation for the rotating
assembly, ensuring durability under the high cylinder pressures
generated by the supercharger.
Cylinder Head and Valvetrain: The engine utilizes a sophisticated Dual
Overhead Cam (DOHC) design with 24 valves. This valvetrain, combined
with the forced induction system, optimizes airflow at high rpm to
achieve the engine's 6800 RPM redline and peak Hp figure.
| Fuel System |
The fuel system is engineered for both high performance and efficiency. It uses a sequential multi-port electronic fuel injection (EFI) system, where each cylinder receives a precisely timed and metered fuel charge for optimal combustion under all loads.
The engine's computer manages this process, integrating with the electronic boost control to deliver a seamless and responsive power curve. A belt-driven supercharger with charge air cooling increases the density of the air-fuel mixture for a significant energy boost without the weight penalty of a larger-displacement engine.
| Lubrication System |
The engine utilizes a high-capacity integrated wet sump lubrication system to handle the demands of forced induction. The total oil capacity is 8.5 US quarts (8.0 Liters) according to some sources, though the user provided data states 7.4 US quarts.
The recommended oil is Mercury FourStroke 25W-40 Marine Oil, a formulation designed to withstand the high temperatures and shear forces present in supercharged applications.
| Cooling System |
Cooling is managed by a high-flow water-cooled system with thermostat and pressure control, critical for maintaining safe operating temperatures in a supercharged engine. It draws ambient water to cool the powerhead.
The system also serves the charge air cooler (intercooler), which reduces the temperature of the compressed air from the supercharger before it enters the combustion chamber, increasing air density and thus power output.
| Mid Section and Lower Unit |
Advanced MidSection (AMS): A signature Verado feature, the AMS cradles
the powerhead on perimeter mounts, moving the engine mounts outward and
aft. This design isolates the powerhead from the transom, drastically
reducing vibration and noise transmitted to the hull and helm for an
exceptionally smooth and quiet ride. Mercury states the 400hp L6 Verado
is 34 percent quieter at 6000 rpm than the leading competitor's 350hp
engine.
Gearcase and Ratio: The engine is mated to a durable, heavy-duty
5.44-inch gearcase designed for high-Hp applications. The primary gear
ratio is 1.75:1. The shift mechanism is forward-neutral-reverse (F-N-R).
Exhaust: The exhaust system is routed through the propeller hub, which
further contributes to noise reduction underwater and at the transom.
| Trim and Tilt System |
The Mercury 400 L6 Verado is fitted with a heavy-duty power trim and
tilt system with SmartCraft programmability. This allows for precise
adjustment of the engine angle to optimize boat performance, handling,
and shallow water operation.
Maximum Trim Range: 20 deg (ranging from -6 deg to +14 deg). Maximum
Tilt Range: 73 deg (ranging from -6 deg to +67 deg) for complete
trailering clearance.
| Propeller Information |
Selecting the correct propeller is essential to fully utilize the Verado 400's supercharged torque band. Mercury offers a comprehensive range of propellers specifically designed for the L6 gearcases. The correct propeller must allow the engine to operate within its 6200-6800 RPM full-throttle range.
The specific pitch and diameter are determined by factors such as boat weight, hull design, and intended use, and are best selected using the Mercury Propeller Selector or dealer expertise.
| Dimensions and Weight |
Shaft Length Options:
20 inches (508 mm).
25 inches (635 mm).
30 inches (762 mm).
Dry Weight (Lightest Model): The lightest configuration of the Verado
400 L6 has a dry weight of 668 lbs (303 kg).
| Maintenance Data |
Every 100 hours:
Change engine oil and replace the oil filter.
Check the outboard for tightness to the boat transom.
Inspect thermostat visually for corrosion and/or for a broken spring.
Check engine water separating fuel filter for contaminants.
Clean and/or replace filter.
Drain and replace gearcase lubricant.
Check power steering fluid.
Inspect battery.
Check wiring and connectors.
Every 300 hours:
Replace water pump impeller.
Check power trim fluid.
Replace high‑pressure in‑line fuel filter.
Replace spark plugs.
Replace accessory drive belt.
| Tightening Torques |
Propeller Nut: 55 lb-ft (75 Nm).
Spark Plugs (NGK ILFR6G-E): 20-22 lb-ft (27-30 Nm).
Cylinder Head Bolts: 15-25 lb-ft.
| Boat Applications |
Offshore Fishing Boats: Its immense low-end torque, ability to maintain
speed in rough seas, and lightweight design make it a premier choice for
serious anglers targeting distant grounds in large center consoles.
High-Performance Center Consoles and Runabouts: It delivers the
thrilling acceleration and top-end speed sought by performance-oriented
boaters.
Multi-Engine Setups: The L6 is popular in twin, triple, and quad
configurations on larger offshore vessels, sport-fishing rigs, and
catamarans. These setups fully leverage the Verado's joystick piloting
compatibility, allowing for intuitive maneuvering and station-holding
capabilities. Pontoon and Tritoon Boats: The supercharged torque
provides the power to propel luxury pontoons with authority,
transforming their performance and onboard experience.
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