Mercury 400XXXL 400HP – Verado V10 35″ Shaft DTS Electric Start in Black

Mercury 400XXXL Verado 400HP V10 Ultra-Long

The Mercury 400XXXL Verado is a specialized 400HP FourStroke outboard engineered for offshore ultra-high transom vessels requiring the industry-first naturally aspirated V10 architecture in the US offshore market. Built upon a 5.7L Dual Overhead Cam (DOHC) powerhead and weighing 695 lbs, this engine features a rare 35-inch ultra-long shaft for maximum hydrodynamic authority. Our dependable outboard propulsion systems is designed to support the displacement-driven torque and digital precision required for professional offshore navigation on the largest multi-engine center consoles and walkarounds. Operational peak performance for the Mercury 400HP V10 occurs between 5800 and 6400 RPM, supported by a class-leading 150 Amp alternator for superior electrical capacity. The 2.08:1 gear ratio translates the 5.7L torque curve into consistent thrust on offshore hulls. Manufactured in the USA, this corrosion-resistant marine engine incorporates SmartCraft Digital Throttle & Shift (DTS) and an integrated High-Output Electric/Hydraulic power steering system to helps support an incredibly smooth experience across deep ocean swells.

offshore 35-Inch Shaft Authority

The 35-inch ultra-long shaft is the defining feature of this model, purposefully designed for offshore transom heights where standard long-shaft motors would lose hydrodynamic grip. This configuration prevents cavitation in ocean swells and helps support consistent forward thrust on the largest deep-V hulls navigating the American coastal environment, providing unparalleled boat control during long-range transits.

Naturally Aspirated V10 Displacement

The 5.7L V10 platform leverages a naturally aspirated DOHC design to provide the smooth, reliable torque that offshore Boaters use. This “displacement over forced induction” philosophy translates to durability, instantaneous low-end grunt for hauling heavy fuel loads, and incredibly smooth power delivery during high-speed offshore runs without the complexity of a supercharger.

150A high-pressure Charging

With a 150 Amp alternator generating 1890 Watts, this V10 engine easily supports the heavy electrical demands of modern offshore angling and cruising. It keeps high-draw radar systems, gyrostabilizers, and multiple 16-inch navigation screens fully powered, ensuring your vessel remains operational during long offshore excursions in the American saltwater environment.

Mercury 3-Year Protection

Every Mercury 400HP Verado V10 outboard is backed by a comprehensive 3-Year Limited Warranty for American owners. This factory-level protection helps support long-term peace of mind and grants access to genuine parts through a vast nationwide marine dealer network, reflecting a commitment to the highest quality and corrosion resistance in the industry.

Maintenance & Longevity

Maintaining clean oil in the 8.0L integrated wet sump lubrication system is vital for preserving tight engine tolerances over time. Always flush the cooling system with fresh water after every saltwater outing.Pro Tip from the Shop:Because 35-inch shaft engines are often part of complex quad-engine setups, strictly monitor the NMEA Gateway for system-wide digital health and regularly grease the heavy-duty steering tube to helps support smooth operation in high-stress offshore environments.