Mercury Marine: Building Great Outboard Engines Since 1939

Mercury Marine is the largest builder of marine propulsion systems in the world, and has been a leading manufacturer of outboard engines since founder Carl Kiekhaefer acquired 300 Thor outboards with the Cedarburg, Wisconsin, manufacturing plant he purchased. Intrigued, Kiekhaefer redesigned the engines, improved the parts, and began making his very big mark on the marine industry. Although in the years following and still today Mercury Marine also has had stern-drive and marinized inboard powerplants among its offerings, outboards remain its core product line.

mercury outboards
Mercury outboards are a favorite among a huge swath of the boating public. Photo by Lenny Rudow.

Today, Mercury produces a line of over 60 outboards including the largest production outboard currently being built in the world, five jet models, a diesel, and one propane-fueled outboard engine. Model lines include FourStroke outboards designed for the recreational boater, SeaPro outboards for the commercial sector, Pro XS models intended for professional-level competition, and the chart-topping Verado line. That range spans from a 38-pound single cylinder 2.5-horsepower eggbeater to the 600-horsepower Verado.

The Mercury Racing division, meanwhile, includes an outboard that top the six- and eight-cylinder Verados, in the form of the 450R — a supercharged V8. Mercury Racing also produces consumer- and competition-grade outboards in multiple sizes from 60- to 450-hp, as well as several race-application gearcases and propellers. Unlike Mercury Marine, however, Mercury Racing also has a big focus on stern drives. In fact, this division builds 12 different racing-application models plus six dedicated drives.

mercury racing 450r outboards
The Mercury Racing outboards, like the 450R, certainly feed the need for speed. Photo via North Point Yacht Sales.

Additional offerings from Mercury include a line of three diesel inboards (2.0-, 3.0-, and 6.7-liter models), six gasoline inboards (4.5- to 8.2-liters), and five different stern-drive drive units. Mercury Marine also offers a wide selection of propellers, and even has a line of inflatable boats.

Pioneering Outboard Technology

Through the years, Mercury has broken a number of barriers and set a number of bars. 1948 was a big year for the company, when they introduced the first in-line-four outboard, the Mercury Thunderbolt. In 1956 they produced the first six-cylinder outboard engine in the form of the 60-hp Mark 75, and one year later introduced through-hub exhaust to the industry. Then in 1962, they broke the 100-horsepower barrier with the first V-6 outboard.

Year by year as outboards became larger and larger, consumers began to wonder how manufacturers could possibly pack more power into an outboard package. Mercury answered that question in 2004, when they broke yet another industry barrier by rolling out the world’s first supercharged four-stroke in-line-six outboard, in the early form of the Verado. Today’s Verado line includes both the supercharged 158.5-cid V-6 in 350- and 400-hp options, and 279-cid V-8s that produce 250- to 300-hp — and as of 2021, the V12 600-hp outboard model.

mercury verado outboards
The newest Verado models have a new look, and a natural aspirated powerhead. Photo via York Harbor Marine Service.

Most recently, for 2023 Mercury introduced the world’s first V-10 outboard, in 350- and 400-hp sizes. These are intended to replace the supercharged V-6 engines in this power slot, with naturally-aspirated, 349-cid powerheads. These engines appear to be a huge engineering success, weighing a mere 27 pounds more than the V-6 models thanks to the use of computational fluid dynamics and advanced composite materials.

But engines alone don’t account for all the unique features and all the tech developments Mercury has brought to the boating world. In 2013 Mercury introduced Joystick Piloting for outboards, bringing with it pod drive-style features like Skyhook virtual anchoring and enhanced dockside handling. In 2015 Mercury introduced Active Trim, a GPS-based automated engine trimming system that boosts fuel economy and simplifies boat operation. And in 2016 VesselView Mobile was released to the public, allowing boaters to tap into Mercury data via their cell phones.

mercury verado 600
The Mercury V12 600-hp Verado has the grunt to power today’s large center console fishing boats, as well as cruisers. Photo via MarineMax Ft. Meyers.

Outboards: The Latest And The Greatest

As we mentioned earlier, the 2021 announcement from Mercury Marine was a big one: the introduction of a 600-horsepower V12 outboard. Since Seven Marine owner Volvo Penta ceased building the Seven Marine 627
prior to Mercury unveiling the 600, it was upon its introduction the largest production outboard engine in the world. Weighing in at 1,260 pounds, displacing 7.6 liters, and available in shaft lengths to 35”, while the 600 is certainly larger than any other Mercury outboard, it shares the Verado line’s sleek, angular shape and look.

Neither the V12 and the V10 platforms have been seen before now in outboards, which means Mercury set more marine industry firsts with them. In the V12 there are, however, several additional features that are completely unique in the world of outboard engines. It has a two-speed transmission, which by all accounts shifts so smoothly as to go practically unnoticed. Just as unusual is this engine’s steering system. Rather than turning the entire motor to direct thrust, the 600 Verado has an articulating lower unit. When you turn the wheel everything above the waterline stays put, while the steerable gearcase turns via an integrated electro-hydraulic steering system. As a result the engines require less mounting space on the transom, and the articulating drive gains 15 more degrees of turning ability for better handling and control. You can check out more details and see the 600 Verado’s introductory video, in Mercury introduces 600HP V12 Verado Outboard Engine.

The V10 also broke some new ground of its own in the tech department. It comes with the first option for a 12/48-volt dual-mode alternator that can be used in conjunction with Navico’s Fathom system. This provides power to a lithium-ion battery system with enough oomph to drive electricity-hungry systems like appliances and climate control. On many boats, having this package will eliminate the need for an onboard generator.

mercury avator electric outboard
An electric outboard, from Mercury? You bet – meet the Avator. Photo via Lenny Rudow.

Mercury has also made some investments in the world of electric outboards, and for 2023 announced the release of it’s first: the Avator 7.5e. Powered by a 1-kWh LiFePO4 battery that pops into a compartment in the motor’s cowl, Mercury says the Avator 7.5e can provide about as much horsepower as a Mercury 3.5-hp FourStroke. The motor is available with tiller or binacle controls and features an integrated digital display. We tested a prototype model and found that it performed as advertised while creating virtually no sound, and zero emissions.

Powerful Outboards: What’s Next For Mercury Marine?

What’s on the horizon for Mercury? It’s a fair bet that they will expand on this new naturally aspirated platform, and its anyone’s guess as to how much we’ll see the use of superchargers in the future. With the disappearance of Seven Marine and the largest Yamaha offering topping out with the F450 XTO outboard, the demand for ever-larger and more powerful outboards is sure to grow. And at least for the time being, Mercury has the monster-motor sandbox all to itself. Mercury has also already announced that additional, more powerful Avator electric motors are in the works. Meanwhile, considering Mercury’s trailblazing attitude it’s also safe to assume that further tech advances and efficiency improvements will come in the smaller outboard line, as well as with new controls, lower units, and propellers. Because if there’s one thing that over eight decades of history has taught us, it’s that Mercury Marine can be depended on to keep coming out with marine industry firsts.

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This article was originally published in May of 2021, and was updated in February of 2023.