Review: Mercury Verado 400R Outboard Motor

RIP big-displacement naturally-aspirated four-stroke outboard motors – Mercury Marine has proven with its L6 Verado engine that supercharging is the way to go. And with 140,000 of these sold in the first 10 years of production, boaters sure agree.

For oldies like me, weaned on lazy naturally-aspirated outboards, the concept of a small-displacement, high-revving supercharged engine is alien. But the more I test Verados, the more I realise Mercury has nailed it. The engines deliver incredible trolling to midrange fuel efficiency combined with blistering top-end performance and, in the more powerful models, much better power-to-weight ratios than the naturally-aspirated competition. And as power output increases relative to piston displacement, so does fuel efficiency. For example, at wide-open throttle the 400R uses only 33 per cent more fuel than a Verado 250 yet develops 60 per cent more power.

The 400R is the current top of the class and has features that make it the logical choice for performance hulls like a Force Crossover 26 I reviewed earlier this year.

Cooling-water intakes beneath the gearcase torpedo enable the 400R to be mounted higher on the transom than conventional lower units, reducing drag yet still providing adequate engine cooling when the hull is completely airborne over an ocean swell. The power steering easily overcomes prop torque and pulling to one side that occurs unless the trim tab on the anti-ventilation plate is angled correctly and even then only at certain leg trim angles.

Another plus is the noise across the entire rev range – there’s no big-block DFI two stroke howl, so normal conversations can be held near the engine. At WOT, for example, the 400R emits the same noise as a four-stroke Mercury F90. The only people who can hear the supercharger whine are those in passing boats, not on board. The only drawback of the 400R is that it needs 98 RON premium unleaded to develop full torque and power.

Verado racing engine

The 2.6-litre inline six power head on the Mercury Verado 400R outboard engine has a self-adjusting chain drive for the double overhead camshafts, and roller cam followers that maintain constant valve clearances, eliminating periodic adjustments. Mercury uses steel cylinder liners that allow reboring and rehoning to take oversize pistons and rings should the engine wear or suffer bore scoring.

The only belt drives are for the supercharger compressor and 70-amp voltage-regulated alternator. The compressor itself is water cooled, with a grille atop the power head allowing plenty of fresh air circulation. Sump oil is cooled via a radiator-style heat transfer cooler. Mercury recommends Quicksilver fully synthetic SAE 25W40 oil and servicing intervals are every 100 hours or annually after the first 20 hours.

Unusually, Mercury uses a two-part upper cowl. Removing the top half gives access to the canister oil filter, compressor and alternator drive belts, the lower half opens the rest of the power head. It’s a bit finicky to refit but the sections are easier to lift off than a one-piece cowl.

The Trade-a-Boat verdict

The Mercury Verado 400 outboard motor made the Force 26 Crossover review boat one for drivers. Many larger trailerable boats are boring in the performance department, but not this combination. Throttle response was instant and the Force 26 sprotsboat was way fun to drive. The 400R just urged me to continually open the throttle and get a bit of air under the hull. It was just like driving a big DFI two-stroke without the howl!

Mercury Verado 400R specifications

Mercury Verado 400R price: $39,810 RRP

With XL with Vessel View kit

Type Supercharged EFI four-stroke six-cylinder racing outboard motor

Rated BHP/MHP* 399.5/405.2 at 6700rpm

Rec. WOT range 6400 to 7000rpm

Piston displacement 2598cc

Bore x stroke 82 x 82mm

Gear ratio 1.75:1

Weights (dry) 309kg XL

                         315kg XXL

OEDA stars 3

* Brake horsepower/metric horsepower or PS