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A New Generation



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5.7L V10 Naturally
Aspirated 400R

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A word from
Mercury Racing

“More low-end torque, more peak horsepower, better fuel economy and full power on 87 octane fuel. The new V10 400R delivers the potent performance and drivability that only Mercury Racing can offer.”

Jeff Broman

Jeff Broman

Director, Mercury Racing Category

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Relentless Innovation
Is In Our DNA

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Racing v10 5.7L Outboard

Deep-Breathing QC4 Technology

Performance you will feel – instantly. A new naturally aspirated V10 5.7-liter powerhead features the deep-breathing Mercury Racing Quad Cam Four Valve (QC4) design with proprietary 92mm throttle body and tuned intake to maximize airflow and power.

Exclusive 92MM Throttle Body

A proprietary 92mm throttle body and tuned intake work with the QC4 head to maximize airflow and power. The exclusive heavy duty throttle body servo motor is designed to produce instant throttle response, while a Mercury Racing fuel pressure sensor provides precise fueling under acceleration to further enhance throttle response.

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Feel the Power

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Full Throttle RPM

Turn on sound for maximum feel

Tap + Hold


Stability at Speed

Mercury Racing Advanced Midsection

The exclusive Mercury Racing Advanced MidSection (AMS) is engineered meet the demands of high-performance boat operation. It supports and isolates the powerhead from the transom to ensure run quality is smooth and quiet at all speeds.

Rugged Mounts

Stiffened engine mounts and precision-fitted heavy-duty guide plates stabilize the engine for enhanced high-speed handling.

Bold Sound

The sound of power. Exhaust is tuned to produce an authoritative growl at startup and idle.

Fire it up

Turn on sound for maximum feel

Optional Tie-Bar

An optional rear tie-bar bracket integral to the Racing AMS provides a strong, ultra-light mounting point for rock-solid precision steering on catamaran and other ultra-high-speed applications.

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5.44 HD Gearcase

The Mercury Racing 5.44 HD gearcase option is ideal for heavy bay boats and multi-engine performance center console boats that require a more-submerged gearcase and benefit from added stern lift. It features a 1.60:1 gear ratio.

Sport Master Gearcase

The race-proven Sport Master gearcase is a surface-piercing design intended for boats capable of exceeding 85 mph, and features low water pick-ups and a crescent leading edge to maximize speed and efficiency. It also features a 1.60:1 gear ratio.

Power to the Water

The new Mercury Racing® Ventera™ propeller is designed to handle big outboard horsepower on fast center consoles, day cruisers and bay boats. This 15-inch diameter, four-blade prop was engineered specifically to carry more load with greater efficiency at high speeds and in semi-surfacing installations.

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Color us gone. Two striking color choices. For your custom finish we offer a ready-to-paint option.

Phantom Black

Phantom Black

Cold-Fusion White

Cold Fusion White


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View Full Specs

Facts & Figures

Full Throttle RPM


Rated HP






Product Details

Horsepower (HP/KW) 400 / 298
WOT RPM 6000-6600
Engine Type V10 (64-degree) with 40-Valve Dual Overhead Cam (DOHC)
Displacement (Liter/CID) 5.7 / 349
Induction System Naturally Aspirated
Fuel Requirements Unleaded Regular 87 Octane Minimum (R+M/2) or 91 RON
Charging (AMP/WATT) 150 / 1890
Throttle & Shift Digital Throttle & Shift
Midsection Racing Advanced Midsection
Integrated Rear Tie Bar Bracket Available
Shaft Lengths (Inch) 20, 25, 30, & 35
Gearcase Sport Master or 5.44" HD
Gearcase Ratio 1:60:1
Dry Weight (LB/KG) 695 / 315
Warranty 3-Year Limited

Tech Features

87 Octane

Experience thrilling performance and full power on readily available 87 octane (91 RON) fuel. Advanced Range Optimization utilizes electronic sensors to precisely adjust the fuel mixture for the best-possible efficiency at all speeds.

87 Octane
Adaptive Speed Control

Adaptive Speed Control

Adaptive Speed Control maintains engine RPM as load changes due to sea conditions or turning maneuvers to maintain boat authority with less control input.

150 AMP Alternator

A powerful 150 amp alternator and Idle Charge battery management help maintain battery charge on boats rigged with power-hungry electronics and audio.

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