Mercury’s V12 Mega-Motor: 600 Horses Of Pure Power

Those who received an invite to attend a February 2021 press event last month at Mercury’s Lake X test center near Orlando knew something big was afoot thanks to the published fleet of boats available for testing, which ranged from a 42-foot Sea Ray SLX 400 Outboard to a Formula 500 SSC with a 54 foot LOA and a tested weight of around 47,000 pounds. While we expected a big outboard, Mercury’s new 7.6L V12 600hp Verado still managed to surprise us with features never seen before on an outboard, like a gearcase that turns independently from the main body of the engine, a two-speed automatic transmission and a host of other features that make it powerful, fuel-efficient, and…civilized.

A Heavyweight Engine for Heavy Boats

As evidenced by the test fleet at Lake X, outboard-powered boats continue to grow to previously unheard-of lengths and the need to power them with fewer engines makes Mercury’s V12 600hp Verado attractive for boat builders. Mercury has been working on this engine for five years and even alerted select manufacturers to the existence of a working prototype two years ago so they could plan future models accordingly.

While some might look at its 1,260-pound weight and deduce the Mercury Racing 450R offers a better power-to-weight ratio with its 689-pound weight but Mercury doesn’t recommend this high-performance engine for fishing boats that will be trolling (or idling) for extended periods of time due to its water pressure demands. The V12 Verado is designed for heavy lifting rather than sprinting, though it managed to push the 54-foot Formula to 69 mph. It even runs on 87 octane regular gas whereas outboards like the 400R need 91 octane gas to make full power.

Twin Mercury V12 600 HP Outboard Engines On A Scout Center Console Boat. Photo: Alan Jones.
Above: Twin Mercury V12 600 HP Outboard Engines On A Scout Center Console Boat. Photo: Alan Jones.

Mercury’s timing for this release couldn’t have been better since Volvo Penta recently pulled the plug on its Seven Marine division that boasted outboards with marinized Cadillac engines that produced up to 627 hp but cost $90,000. While the $77,000 price tag for the V12 Verado isn’t petty cash, buyers are getting some serious technology for their money.

Since 2008, Mercury has spent more than $1.5 billion on R&D and the V12 Verado is one of the beneficiaries of that investment in the future. Unlike Seven Marine’s approach to mega-power, there is no automotive equivalent to Mercury’s powerplant. This purpose-built design is important because the missions of a car and boat are drastically different. While a boat getting on plane does ease the load on an engine, compared to a car’s low rolling resistance, it’s still the equivalent of driving up a steep hill all the time.

Also, cars typically only run at about half the speed it’s capable of while outboards are designed to run at full speed for extended periods of time. Mercury’s advanced Fond du Lac, Wis. foundry allowed them to “brew” their own, using the largest die-cast machines in North America to produce the biggest outboard engine ever made.

An Innovative Feature: The V12 Powerhead Doesn’t Move

An independently articulating gearcase offers several benefits like allowing more of these motors to be squeezed together on a transom without bumping into each other when in joystick mode. Amazingly, they can be mounted on 27-inch centers, which is only 1 more inch than is required for most other multi-engine installations. Another benefit is the ability for the gearcase to turn 45 degrees in each direction when using the Joystick Docking Outboards system for more effective maneuvering instead of the 30-degree articulation when in normal operation. Because the driver doesn’t see the motors rotate when turning the wheel, a welcome addition is the rudder position indicator.

Because the entire engine isn’t rotating, the V12’s lower unit can pivot more quickly, thanks to the integrated, drive-by-wire, electro-hydraulically-actuated steering system. This level of control will be very useful for situations like making quick corrections when running in rough seas to avoid catching a wave wrong or avoiding crab pots. A contra-rotating prop system with a four-blade up front and a trailing three-blade prop give it plenty of bite without having to resort to a large-diameter single prop, which would create more drag. A wide variety of prop choices is available with diameters up to 18.25 inches.

Those who have only one V12 on the transom (you know some builder will put this on a mega-pontoon) can take advantage of the new DTS control’s Quick Steer feature that allows the driver to turn the motor to its stop with only a quarter-turn of the wheel.

Two-Speed Automatic Transmission

In 2007, Mercury Marine showed the press a variable-pitch propeller called the SmartProp that could start with a lower pitch for hole shots then change to a higher pitch when the load was reduced as the boat got on plane. It worked well but never made it to market, likely because of issues like reliability and high maintenance requirements. For the V12 Verado, Mercury found another solution by using a two-speed transmission, made by ZF, the German company that also built the lower units for Seven Marine’s beastly outboards.

The gear ratios are close together starting in first, which has a 2.97:1 gear ratio. Because the transition is so smooth, you have to watch the tachometer to notice when it shifts to its 2.50:1 second gear. The only time I could feel it shift happened after dropping a Sea Ray SLX 400 down from 40 mph to around 20 mph. It was still on plane and in second gear when I jammed the throttles forward, causing the twin engines to downshift to first like a car when a driver passes on a busy two-lane highway. This gave it a satisfying surge of acceleration that showcased the power of the V12. Because the gearcase is located just below the powerhead instead of in the lower unit, Mercury was able to employ a smaller diameter bullet for less drag.

Shifts are incredibly smooth thanks to the V12’s multi-plate wet clutch instead of the usual cone clutch, which produces a pronounced clunk when shifting. The difference between the two technologies is most apparent when using the joystick’s Skyhook virtual anchor, which can precipitate frequent shifting to remain in one position and heading in strong winds or current.

No-Hassle Maintenance: Easy Access Cowling

The 600hp Verado features unparalleled access for routine maintenance thanks to the service hatch that opens the entire cowling’s top with the push of an electronically-actuated button. Here, there’s access to the oil dipstick to check the level of the massive 14-quart reservoir, though Mercury also allows owners to check it electronically. There’s a second dipstick for the transmission fluid and both dipsticks are designed to accept a tube that can extract and refill the fluids.

The gearcase oil can also be changed without removing the boat from the water. For convenience, Mercury even put the oil filter on top of the engine for easy replacement. The first scheduled maintenance event occurs at 200 hours and the bolted-on cowling doesn’t have to be removed for 1,000 hours or five years, whichever comes first.

Because most modern mega-boats feature all the electronic bells and whistles available like 1,000-watt stereos, air-conditioning, gyro stabilizers, grills and refrigerators, the V12 Verado has a massive 150-amp alternator that can keep batteries charged up without using generators or exotic lithium-ion battery banks to keep up with demand.

Performance: It’s Smooooth!

Perhaps the most startling attribute of the quad-cam, 7.6L V12 600hp Verado is its smoothness and quietude. Twelve-cylinder engines are inherently vibration-free because of their perfect balance, which is why luxury car companies like Bentley and Jaguar employ them. Doing the math shows a cylinder is firing for every 60 degrees of rotation of the crankshaft, which evens out any surge caused by a piston’s movement. This engine is normally-aspirated, like its V6 and V8 Verado counterparts and the large displacement has plenty of torque needed to get the biggest boats on plane quickly with a power curve is strong and very linear.

scout 400 lxf with Mercury 600 verado
Thanks to all the torque, a mere pair of V12 Verados has no problem powering large, heavy boats, like this Scout 400 LXF – a 15,000 pound (dry weight) center console. Graphic via Scout Boats.

The V12 Verado is one of the quietest engines I’ve tested. Even with four of them on a transom, passengers were able to have a normal conversation when at cruise speeds. At idle, they’re preternaturally quiet not only due to Mercury’s mitigation of intake sounds, which make up a good deal of the noise but also due to the absence of a tell-tale stream of water splashing on the surface, which is a feature found on every other outboard.

The 600 horsepower version of the V12 Verado is probably just the opening gambit from Mercury. Expect higher-horsepower variants to follow. If Mercury can get 400 horsepower from its supercharged 2.6L 400R outboard, a supercharged 7.6L block could theoretically produce a 1,268 horsepower outboard.

For more information about the rest of Mercury Marine’s offerings, see Mercury Marine: Building Great Outboard Engines Since 1939.

Editor’s Note: This article was updated in March of 2022.

Written by: Alan Jones

Alan Jones is a marine journalist who has tested more than a thousand boats and written more than 500 boat reviews and video walkthroughs online, including fishing boats, cruisers, PWC, pontoons and ski boats. If it floats, he's tested it. One of his passions is testing new products that make boating easier and safer. Currently the president of Boating Writers International, Alan is a gearhead who's tested almost every engine that's come out in the last 20 years. He also loves fishing of all kinds.


grady-white canyon 376
Joystick Boat Controls
Category: Boat Engines
Joystick controls make running a boat easier than ever.