Mercury 400CXXXL 400HP Outboard – 35in Shaft, Counter Rotation, DTS

Secure the ultra-long, counter-rotating Mercury 400CXXXL to eradicate thrust loss on towering custom offshore vessels. The massive 5.7-liter V10 block forces immediate acceleration, pushing heavily loaded multi-engine catamarans over aggressive ocean swells. Taping your transom verifies this 35 inch ultra long shaft outboard places the water intakes deep enough for safe operation.

Prevent dead electronics while slow-trolling offshore by leveraging the massive 150-amp alternator as a dedicated onboard power plant. The system replenishes drained battery banks continuously at low RPM. Mercury casts the 316 kg assembly with low-copper marine alloys under the factory finish. This structural barrier stops galvanic decay completely when repowering large offshore vessels for extreme coastal use.

Key Features of Mercury 400CXXXL

- Advanced Range Optimization: Leans the fuel mixture automatically at cruise via EFI, maximizing your tournament fishing range significantly.
- 35-Inch XXXL Shaft: Reaches incredibly deep beneath towering 50-foot offshore transoms, keeping the propeller fully engaged in undisturbed green water.
- Counter-Rotating Gearcase: Offsets the lateral thrust of standard engines, eliminating steering pull and keeping massive catamarans tracking dead straight.
- Integrated Power Steering: Provides electro-hydraulic mechanical assist, delivering sports-car-like handling and zero steering fatigue during long offshore runs.
- Massive 150-Amp Alternator: Generates tremendous electrical output, keeping deep cycle house batteries topped off during long tournament fishing days.
- Low-Copper Marine Alloys: Forms a rigid structural barrier under the paint, resisting severe saltwater degradation across decades of heavy exposure.
- Submerged Exhaust Routing: Channels hot gases out through the propeller hub, keeping the aft deck completely free of exhaust smoke.
- Top-Cowl Service Door: Lets operators check the 9.5L engine oil level rapidly on the water, preventing dangerous low-lubrication running scenarios.
- Heavy-Duty 2.08:1 Gearcase: Deflects submerged debris physically, protecting the hardened steel internal gears from catastrophic offshore impacts.
- EPA Compliant Technology: Burns fuel with strict efficiency, ensuring peak performance while meeting modern clean-air environmental standards.

Why Choose Mercury 400CXXXL

You select this specialized 35-inch motor strictly to complete a twin or quad engine array on massive 50-foot offshore hulls. Substituting a standard 30-inch model will cause catastrophic water pump starvation. Upgrading your mercury digital throttle network is required for multi-engine communication.

- Confirm a 35-inch vertical drop from the massive mounting bracket to the keel line.
- Network the DTS module securely to your master helm command center.
- Avoid heavy smoke and oil slicks using advanced V10 four-stroke internal lubrication.

Ideal Application and Vessel Fitment

This 35-inch counter-rotating V10 thrives on custom 50-foot offshore walkarounds, deep-V mega center consoles, and massive multi-engine catamarans requiring an ultra-long shaft. It reaches incredibly deep beneath elevated transom brackets to grab solid water, resisting propeller blowout during extreme ocean cresting. Operating as the port-side anchor in quad arrays, it provides relentless naturally aspirated V10 thrust and electrical power for serious blue-water tournament anglers pushing far past the sight of land.

Warranty, Support and Maintenance

Authorized recreational operation receives a 3-Year Limited Warranty alongside a 3-Year Corrosion Warranty. Registered commercial applications fall under a strict 1-Year Limited Warranty with zero corrosion coverage applied to the block. Scheduled maintenance requires replacing gearcase lubricants and changing oil filters at manual-specified intervals. Always save all physical service records. Your engine serial number acts as the only way to source exact genuine replacement parts. Mulmotor provides pre-purchase product guidance and order-related customer support.