When details of Yamaha’s new XTO Offshore outboard were released last week, it triggered a plethora of comments about the engine’s weight on social media and boating and fishing forums.
The 25-inch shaft version of the engine weighs 952 pounds, the 30-inch weighs 977 pounds, and the 35-inch version checks in at 999 pounds.
Performance-boat enthusiasts compared the XTO Offshore to Mercury Racing’s Verado 400R, which weighs 668 pounds in its lightest configuration. It’s a supercharged inline 6 with a displacement of 2.6 liters and is used on everything from center consoles to high-performance catamarans.
The XTO Offshore is a naturally aspirated 5.6-liter V-8 that was designed for a different application, said Ben Speciale, president of Yamaha Marine Group. Speciale said development of the new engine started with a target propeller size for large offshore fishing boats.
“What we want to do is spin a bigger prop, and to spin a bigger prop you need a bigger prop shaft, diameter and gears, and much more displacement in the engine to give you the torque,” he said. “We want bigger charging systems and integrated steering systems. The weight is the weight.”
Speciale continued: “We’re pushing boats that weigh 30,000 pounds plus, so what’s 100 pounds? I don’t see it as an issue. 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.”
Divide 952 pounds by 425 hp, and you get 2.24 pounds per horse. Yamaha’s F350 has a power-to-weight ratio of 2.18 pounds per horse. The XTO Offshore makes its peak power at 5,500 rpm. (Yamaha doesn’t release torque specifications.)
“It’s easy to make horsepower,” Speciale said. “Durability is difficult.”
I drove four boats with rigged with the XTO Offshore. A Jupiter 43 SF center console with quads had an impressive top speed of 62 mph at 6,000 rpm and needed a typical amount of time to plane in a hard start. The boat weighed 26,797 pounds and has a deep-vee hull with 24 degrees of transom deadrise.
I ran a twin-step Contender 39ST with triples to a top speed of just over 71 mph at 5,900 rpm. The boat had strong mid-range punch when I nailed the digital throttle from cruising speed. A single-engine Sportsman Masters 267 bay boat offered the purest evaluation of the motor. It planed in a heartbeat and sprinted to a top speed of 61.2 mph in seconds. A 33-foot Grady-White Canyon center console that tipped the scales at 13,194 pounds with twin XTO Offshores jumped on plane in seconds with hardly any bow rise.
One of the benefits of all that power is the ability to swing large-diameter props. The test boats had 16- or 16-3/8-inch-diameter stainless wheels, and that translated into a strong bite in turns. Even on the stepped-bottom Contender, the tachometer never dropped off in turns that were tighter than most skippers would make at 60 mph. With the conventional vee-bottom boats, the props held their bite without slipping when I turned hard over.
Among the design innovations is the location of exhaust ports, above the outboard’s anti-ventilation plate. When you’re running at less than 2,500 rpm, the exhaust exits through these ports, not through the prop hub. This means the props are biting into denser, clean water, which makes them much more effective.
Yamaha says the XTO Offshore has 300 percent more reverse thrust than the F350. All the boats I ran were very responsive in reverse and had plenty of torque to back down on any fish. I and other journalists noticed that the engines are louder above 4,500 rpm than other 4-strokes.
The XTO Offshore mounts on the same 28.5-inch centers as the F350, with the same bolt pattern. Displacement is 5,559 cubic centimeters/5.6 liters; bore and stroke is 96mm by 96mm.
Oil capacity is 8.2 quarts, which might seem like a lot, but it’s for long-range durability. The same goes for the double-overhead camshaft design.
Retail pricing for the engine in gray starts at $44,250 for the 25-inch shaft in right rotation and $45,185 in left rotation. The 30-inch shaft retails for $45,000 (right) and $45,935 (left). The 35-inch model is $46,120 (right) and $47,060 (left). The XTO Offshore has a five-year warranty.