The Mercury Verado 600 is an outboard motor by definition, but only because it bolts to a boat’s transom. In the past decade outboards have grown ever more powerful, but the basic design has not really changed since Ole Evinrude screwed his brass kicker to the back of a rowboat. The Verado 600 is a different beast; it’s a collection of new ideas that together could redefine outboard power for large boats.
The spec sheet alone is impressive: 600 horsepower from a 7.6-liter V12 powerhead driving contra-rotating propellers. But this is more than a big motor. A two-speed automatic transmission provides gear ratios for hole shot and efficient cruising. The gearcase is steerable, while the powerhead stays stationary. The cowl opens like the hood of a Mercedes, to accommodate all regular maintenance. Operating at idle or speed, the motor is almost silent. The performance, sophistication and luxury of the Verado 600—and its projected $77,000 price tag—is a match for the million-dollar center consoles and dayboats it is most likely to power.
“We’ve dedicated substantial investment and years of effort toward enhancing our ability to turn highly creative ideas into practical, functional and dependable solutions,” said Tim Reid, Mercury Marine vice president of development and engineering. He was referring to the $1.5 billion invested in R&D and manufacturing expansion since 2008. The payoffs are listed here.
The Verado 600 shares its basic architecture, a 64-degree cylinder angle, double overhead camshafts and four valves per cylinder, with the Mercury 4.6-liter V8 engines introduced in 2018. “The bore and stroke is larger than the V8,” said Reid, “and the V12 powerhead is just a little wider. The V12 configuration allows us to have the desired displacement and still maintain 27-inch, center-to-center spacing for multiple engines on the transom, which was one of our key design targets.”
The V12 also has perfect primary balance and so is silky smooth. The powerhead is supported by an Advanced MidSection (AMS) similar to the AMS found on the in-line six-cylinder Verado models, an aluminum halo with four elastic mounts that isolate the engine from the boat. The trim/tilt pivot is moved farther aft on the Verado 600, which Reid says allows the motor to tilt fully within the same motor well as Mercury V8 models. In the end, that’s a convenience for boat builders. To keep up with battery demand on large boats, alternator output is 150 amps.
A multi-clutch, two-speed automated powershift transmission, designed by Mercury and manufactured in Italy by ZF Friedrichshafen AG, is located below the powerhead. First gear is 20 percent lower than second, which Reid explains delivers 20 percent more torque to the props. The ratio at the prop shaft in first gear is 2.95:1 and in second gear is 2.50:1, much lower ratios than the 1.75:1 gears in a Verado 300, for example. This amplifies the torque of the engine to manage twin props with tremendous blade area, which is just the prescription for lifting a heavy boat on plane and holding it there at lower speeds. Transmission shifting is managed by the engine controller, based on torque demand. In a multi-engine rig, each engine will shift individually.
“There’s no master control for shifting multiple engines at once, and that’s by design,” said Reid. “If four engines shifted at precisely the same moment you’d feel it in the boat, but by staggering the shifts by fractions of a second, it’s a smooth transition. Unless you are looking at the tachometers you won’t notice the shift.”
The engine will downshift in some situations, such as accelerating smartly from a slow cruise speed, just as an automobile will shift when you accelerate to pass. There is no manual shifting function except for selection of forward-neutral-reverse.
The props for the Verado 600 were developed by a team led by Roger Koepsel, master engineer with more than 50 years at Mercury Propellers. To maximize blade area, contra-rotating propellers feature four blades on the forward prop and three on the aft prop, as also seen on the MerCruiser Bravo III sterndrive. The front and rear prop shapes and diameters are also very different.
Nine prop sets have a pitch range of 23 to 37 inches—the low gear ratio permits a lot of pitch and also keeps propeller rotational speed down, which improves prop efficiency and boosts boat speed at cruising rpm. Front prop diameter ranges from 18.25 inches for the 23-pitch prop to 16.5 inches for the 37-pitch prop, while diameter of the rear prop ranges from 16.75 to 15.0 inches. When viewed in profile, the blades of the forward prop sweep back to overlap with the rear prop. The function of the rear prop, Koepsel explains, is “swirl recovery,” the capture of energy from the front prop that is dissipating outward, rather than pushing the boat forward.
Because all shifting is accomplished in the transmission, the gearcase is only six inches in diameter, a big hydrodynamic bonus. According to Mercury, a single prop with equal blade area would need to be 22 inches in diameter, requiring a much deeper gearcase that would produce a lot of drag. An average propset for the Verado 600 will cost about $3,300.
Only the gearcase pivots to steer the boat. The powerhead is always stationary. This eliminates boat-mounted steering, allows multiple engines to be mounted close together, and permits greater range of steering. In joystick mode, the gearcase can pivot up to 45 degrees port or starboard, compared to about 30 degrees for a traditional design. This gives the engines more authority to move a heavy boat at low speeds. At operating speed the steering range is limited to about 30 degrees. The steering function is similar to that of a pod drive. A signal from the digital helm is translated to hydraulic
action on a steering rack within the engine.
Ease of Maintenance
A big motor has a big cowl, which is not easy to remove. That’s why Mercury devised service access through a hatch in the top of the cowl, for all maintenance required for 200 hours of operation. The oil dipstick, fill point and oil filter, and dipsticks for the gearcase lube and transmission fluid are all within reach. Each dipstick tube has a snap fitting for an extraction pump used to suck out spent fluid. The engine oil capacity is an astounding 14 quarts, one reason the motor can go 200 hours on fresh synthetic oil. The cowl comes off at 1,000 hours or five years to change spark plugs and service the water pump. The water pump is oversized and designed to be very durable.
Alongside the Verado 600, Mercury has introduced Next Gen Digital Throttle & Shift (DTS) controls, which are standard with Verado outboards and feature improved ergonomics. The base of the Premier DTS binnacle control has a display screen that reports system status and maintenance information.
Bigger and Bigger
The premise of the Verado 600 is to reduce the number of engines on the transom; three Verado 600 motors could replace four Verado 400 outboards, for example, and deliver more power with less drag in the water, slightly better fuel economy, and a host of advanced features. It’s the same idea that launched the now-defunct Seven Marine mega-outboards, but executed with more resources. A Verado 600 is twice as heavy as a Verado 400, however, so in this example engine weight would increase by more than 1,000 pounds, which may not be significant on many boats.
Mercury anticipates the Verado 600 will move outboard power onto boats over 60 feet LOA. Note that the Verado 600 is offered in a 20-inch length for, you guessed it, the pontoon owner who needs to rule the lake. Everyone wants a big outboard.
Type: 64-degree V12 four-stroke
Displ.: 7.6 liters/464 cubic inches
Bore x Stroke: 3.8” x 3.4”
WOT RPM Range: 5600 to 6400
Fuel Requirement: 87 octane
Final Drive Ratio: 2.97:1/2.5:1
Alternator Output: 150 Amp
Dry Weight: 1,260 pounds
Available Lengths: 20”, 25”, 30”, 35
This article was originally published in the April 2021 issue.