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Bulking Up

Outboards continue to grow in power, with some manufacturers now offering V-8 engines.

Brian Turner owns multiple businesses on Florida’s west coast. When he wants to fish for marlin and sailfish, he takes his outboard-powered center console about 130 miles to “The Steps” in the Gulf of Mexico.

“I like to go fast, and I don’t get a whole lot of time off,” says Turner, 43, of Bradenton, Florida. “I’ve always liked the speed and the fishability that come with the center console.”

He got his first center console, a 42-foot Yellowfin, about five years ago and last year had the company build him a custom carbon-fiber version with triple 350-hp Yamaha four-stroke outboards. Haulin’ Grass runs at 65 mph in good conditions and at about 55 in rougher stuff. “I’m trolling for marlin in two and a half hours,” Turner says.

During the last decade, a growing number of anglers have moved into larger, faster, more nimble outboard-powered center console fishing boats. “It’s all about fishability, performance and fuel economy,” says Yellowfin Yachts President Wylie Nagler. “I can cover more distance and fish more miles in the same day.”

The bigger-is-better trend has been in vogue for some time with both open boats and outboards. It’s been a chicken-and-egg relationship. Larger boats spurred the development of larger (and mulitiple) engines. Greater horsepower led to bigger boats.

“Engine development guided or was a major factor in the development of these boats,” says Michael Peters, president of Michael Peters Yacht Design in Sarasota, Florida, which has nearly a dozen outboard-powered center consoles on the drawing board. “People changed the way they fish to use outboards. I wouldn’t say the outboards are great for fishing; I would say everybody modified their fishing because outboards are great for propulsion.”

Seven Marine has had its high-output V-8 outboards since 2011, including a 627-hp model, the most powerful outboard in the industry. In late 2017, Suzuki introduced its DF350A, a high-compression V-6 outboard with what it calls “contra-rotating” twin propellers. In May, Mercury and Yamaha unveiled naturally aspirated outboards with V-8 powerheads—marking the first time the industry has had three manufacturers offering V-8 outboards.

Yamaha’s new XTO Offshore 425-hp outboards are designed to push big saltwater boats.

Yamaha’s new XTO Offshore 425-hp outboards are designed to push big saltwater boats.


Yamaha introduced the XTO Offshore this past spring, a 425-hp outboard with a 5.6-liter displacement, available in 25-, 30- and 35-inch shaft lengths. It runs on 89 octane fuel and has a bore and stroke of 96 by 96 millimeters, with a compression ratio of 12.2-to-1 and double overhead camshafts. The outboard’s direct fuel-injection system has five pumps, three electrical and two mechanical. An electronic control module monitors fuel pressure.

For anglers, the exhaust system is intended to improve reverse propeller thrust. When the engine is running below 2,500 rpm, the exhaust exits above the anti-ventilation plate, letting the propellers get a cleaner bite. Yamaha says the XTO Offshore has 300 percent better reverse thrust than the company’s 350-hp outboard.

The XTO Offshore also has a hydraulics-free electronic steering system. An electronic motor in the tilt tube moves the outboard back and forth with input from the steering wheel, and there’s a manual override if there’s a problem with the main system.

To run the electronics that fishermen use, the engine produces up to 90 amps of total power with a net output of 59 amps at idle, 72 at 1,500 rpm, 66 at 3,000 and 46 at wide open. For easier servicing, the lower unit gear lube can be changed with the boat in the water, and the engine has 73 degrees of tilt-up range to get the entire engine out of the water.

The XTO Offshore has a 6-inch-diameter gearcase, compared to the 5.25-inch gearcase on the F350, and the props come in diameters from 16 to 17⅛ inches, and in pitches from 15 to 25 inches. The engine is designed to mount on 28½-inch centers, and it has the same bolt pattern as the F350.

The 25-inch version weighs 962 pounds, the 30-inch shaft length checks in at 977 pounds, and the 35-inch tips the scales at 999 pounds. Ben Speciale, president of Yamaha Marine Group, says those weights are fine. “We’re pushing boats that weigh 30,000 pounds-plus, so what’s 100 pounds? I don’t see it as an issue,” Speciale says. “The 350 was the same way. The engine’s kind of heavy if you look at a boat of today, but if you look at a boat of tomorrow, it’s not heavy at all. It’s easy to make horsepower. Durability is difficult.”

Retail prices for the XTO Offshore start at $44,250 for a 25-inch shaft with right rotation and $45,185 with left rotation. The 30-inch shaft retails for $45,000 with right rotation and $45,935 with left. The 35-inch shaft is $46,120 with right rotation and $47,060 with left.

The new Mercury V-8 outboards have the narrowest profile and mount on 26-inch centers.

The new Mercury V-8 outboards have the narrowest profile and mount on 26-inch centers.

Mercury Marine

Mercury Marine’s new outboards with V-8 powerheads, also introduced this past spring, displace 4.6 liters (279 cid), and they are available in Verado, FourStroke and Pro XS models from 200 to 300 hp. The engines have a quad-cam design and extended exhaust runners for improved flow and torque.

The lightest dry weight is listed at 527 pounds for the FourStroke 250- and 300-hp models, which gives them a weight-to-power ratio of 1.76 pounds per horsepower, suitable for lighter-weight applications, such as bass boats. Mercury says the engine is the lightest in its class by 20 pounds. The Pro XS 250- and 300-hp models weigh 505 pounds.

Advanced Range Optimization adjusts fuel delivery, and the closed-loop fuel control uses a wide-range oxygen sensor for fuel economy. With their narrower profile, the Mercury outboards mount on 26-inch centers. A service door on the cowling opens for dipstick checks and oil fills. The engines generate 20 amps at idle and 85 at wide open, and raise the idle rpm to charge the battery when voltage is low.

The Verados are considered Mercury’s luxury models and have a midsection designed to mitigate noise and vibration. Mercury says its Verados are 20 percent quieter at idle and 35 percent less noisy at cruise and wide open than comparable engines from other manufacturers, with 66 percent less vibration at the helm. “There’s not a quieter engine on the market than Mercury’s,” says John Pfeifer, president of Mercury Marine. “We invest a lot into ensuring that every outboard we manufacture meets the demands of the marketplace.”

Mercury’s 350 and 400R Verados continue to be the company’s most popular for offshore use, and Pfeifer doesn’t see the size of boats getting any smaller. “Five years ago, walking around the Ft. Lauderdale boat show, you might have seen one or two triple or quad applications,” he says. “The consumer wants a large, center console boat with multiple outboards on the back. As fishing continues to grow in popularity—it’s currently the number-one-ranked outdoor activity—so, too, will the desire from some customers who want a bigger fishing boat.”

When Mercury introduced the Verado line in 2004, “fly-by-wire was the game changer,” says John Caballero, sales and marketing director at SeaVee Boats. “When they packaged the fly-by-wire and the power steering, now you had a technological interface between the operator and the motor.”

In the early days of multiple-outboard configurations, he says, people were intimidated by the multiple levers for shifting and throttling. With today’s digital shifting, “it doesn’t matter if it’s a triple or a quad. You operate it like a twin.” Pricing ranges from $23,540 for a 250-hp Verado to $24,965 for a 300-hp Pro XS.

Suzuki’s DF350A uses twin “contra-rotating” propellers to improve maneuverability on big boats.

Suzuki’s DF350A uses twin “contra-rotating” propellers to improve maneuverability on big boats.


Capt. Ron Mitchell of the Bandit Fishing Team had quad 300-hp Suzukis on his Sea Hunter 39. “When I got the 350s, it completely changed the boat,” he says.

Much like Yamaha did with the XTO Offshore, Suzuki designed the DF350A as a big engine to push big boats. The 55-degree V-6 block displaces 267.9 inches (4,390 cc) with a bore and stroke of 3.74 by 3.82 inches. It has multipoint sequential electronic fuel injection with lean burn and an oxygen sensor, and the compression ratio is 12-to-1, which is comparable to the Yamaha XTO Offshore’s.

Falling in between the Mercury and Yamaha on the weight scale, the DF350A weighs 727 pounds for the 25-inch shaft and 747 pounds for the 30-inch. That gives the 25-inch model a weight-to-power ratio of 2.08 pounds per horsepower. (Suzuki doesn’t offer a 35-inch shaft.)

The DF350A has what Suzuki calls dual “contra-rotating” props, which have a 15½- inch diameter and pitch ranges from 19½ to 31½ inches. The extra propeller blades provide improved torque for getting big boats on plane, and a better bite for backing down on a fish or maneuvering around docks. “I can spin the boat in place on an axis with those motors,” Mitchell says. “Right when the lines go off, we’re spinning that boat around and going after that fish. It spins around like a 21-foot boat.” He says he picked up 7 to 10 mph with the new outboards while keeping fuel economy about the same as with the 300s.

Retail pricing for the DF350A starts at $32,825 with a 25-inch shaft.

Honda introduced its biggest outboard, a 250-hp model, at last year’s Miami boat show.

Honda introduced its biggest outboard, a 250-hp model, at last year’s Miami boat show.


Honda Marine, the originator of the four-stroke outboard, introduced a new 250-hp engine earlier this year. The biggest outboard the Japanese manufacturer offers, the BF250, is a 60-degree V-6 that displaces 3.6 liters and has an upgraded air-induction system, variable idle charging and a new gearcase design.

The engine has a bore and stroke of 89 by 96 millimeters, and maximum rpm is 6,300. The lower unit gear ratio is 2-to-1, and the 90-amp alternator has a maximum charging power of 60 amps.

For an improved hole shot, the engine has Honda’s Boosted Low Speed Torque, or BLAST, system, which uses an air-fuel link timing control to improve low-speed acceleration. The manufacturer’s digital Intelligent Shift and Throttle, which can be integrated for up to four engines and two control stations, is an option.

The BF250 is available in 20-, 25- and 30-inch shaft lengths and weighs in at 600, 613 and 622 pounds, respectively. That gives the 25-inch shaft length a weight-to-power ratio of 2.45 pounds per horse. Pricing was unavailable.

Evinrude is the lone manufacturer of two-stroke outboards, which have better bottom-end torque.

Evinrude is the lone manufacturer of two-stroke outboards, which have better bottom-end torque.


The lone two-stroke manufacturer in the game is Evinrude, whose E-TEC G2 series ranges from 150 to 300 hp. The 300-hp outboard has a 74-degree V-6 powerhead with a bore and stroke of 3.854 by 3 inches and a displacement of 3.4 liters. Maximum rpm is 6,000, and total alternator output is 133 amps, with a net of 50 and 14 produced at idle. It retails for $26,000.

For Capt. C.A. Richardson, who spends most of his time in skinny water going after tarpon and bonefish, the torque and lighter weight of a two-stroke are critical. He runs a Hell’s Bay Marquesa flats boat powered by a 90-hp E-TEC outboard.

“I fish in water from inches deep to up to 3 feet or 4 feet max,” Anderson says. “The hole shot is amazing, and it’s so reliable. Even at rest when the boat is off, the ability to have a motor that’s lighter is everything. The litmus test is when we’re at idle speed and I hit that throttle, and it jumps on plane.”

E-TEC G2 engines have a magneto charging system, hydraulic steering integrated into the midsection and an onboard two-stroke oil reservoir for a cleaner transom and simpler rigging. They are offered in 20-, 25- and 30-inch shaft lengths, depending on the model. The 150-hp engine weighs 300 pounds, for a weight-to-power ratio of 1.79 pounds per horse.


Seven Marine

Seven Marine outboards have a powerhead that’s derived from a General Motors supercharged aluminum-block V-8. They are available with horsepower ratings of 527, 577 and 627.

The V-8 has a bore and stroke of 4.065 by 3.622 inches and a compression ratio of 8.6-to-1. A closed cooling system resists corrosion. Shifting is done through a ZF Marine transmission, and the gearcase has dual pinion gears that are built to handle 1,700 hp.

The engines come in 20- and 25-inch shaft lengths, and in 1-inch intervals from 25 to 39 inches. The 20-inch outboard weighs 1,094 pounds for a weight-to-power ratio of 1.74 pounds per horse.

Stainless-steel headers reduce noise, and the fuel system has Quick Start technology, which automatically primes when the key is turned on. Seven Marine targets the growing fleet of big center consoles with its outboards. Prices range from around $70,000 to $120,000 depending on the model and options.

Diesel, Anyone?


Michael Peters says the next gamechanger for center consoles could be a lightweight diesel outboard of significant power.

British company Cox Marine has a 300-hp diesel outboard, the CXO300, that is being used in military and commercial applications. “While we were not initially targeting the recreational market, high demand has led us to readjust our direction,” says Joel Reid, Cox’s global sales director.

The company has displayed the engine at boat shows, and interest was high. “The saltwater fishing segment will be the main application in markets such as Florida, Texas and Georgia,” Reid says. “Overall, it might represent between 15 and 20 percent of engines provided to the U.S. market.”

Cox Marine says the CXO300 saves about 25 percent in fuel consumption compared to a 300-hp gas outboard. The increased bottom-end torque that comes with a diesel should also come in handy on big center consoles. Cox says the CXO300 has “100 percent higher peak torque at the crankshaft than the leading 300-hp outboards, 60 percent higher when compared with a leading 350 hp. This difference is amplified when looking below the midrange rpm.”

The CXO300 is available in 25-, 30- and 35-inch shaft lengths. It installs on 28½-inch centers and is available in two gear ratios, 1.227-to-1 and 1.46-to-1, for heavier boats that spin bigger props. Cox says engine life is two to three times longer than a gas outboard, and that the CXO300 needs “dry” service once a year, or every 1,000 hours.

This article originally appeared in the premier issue of Outboard magazine.