Industry Firsts Include Direct Injection and Integrated Electric Steering System Yamaha V8 XTO Offshore™ Outboard Offers the Extreme

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The new Yamaha V8 425 XTO OFFSHORE outboard is designed to take Yamaha’s premium quality brand position to a higher level with extreme power and thrust, toughness and reliability, system integration, control, convenience and customer care. Yamaha has achieved many of these extremes by rethinking the outboard and its related systems, and through the application of technologies new to the industry.

“This is an integrated outboard system, designed to push the heaviest offshore boats and yachts,” said Ben Speciale, Yamaha Marine Group President. “The new Yamaha V8 425 XTO OFFSHORE has 5.6-liters tremendous thrust and 425 horsepower. The Yamaha V8 425 XTO OFFSHORE provides extreme performance for the biggest boats. Combine it with the latest generation of Helm Master® and Yamaha’s CL7 Display, and you have benefits offered nowhere else.”

Extreme Power and Thrust

Pushing the heaviest offshore boats and yachts requires driving extreme, large propellers, a massive, rugged gearcase and an extreme powerhead.  As the first four-stroke powerhead in the outboard industry to use Direct Injection, the V8 XTO Offshore is already a legend, spraying fuel at high pressure directly into the combustion chamber, rather than the intake track, just before the intake valve. This greatly improves atomization and increases the effectiveness of the fuel burn for maximum power and efficiency.

The Direct Injection system features five fuel pumps and injection pressure up to 2900 PSI. The three-stage fuel pressure system is in part comprised of two independent fuel pumps within the Vapor Separator Tank (VST) that activate at specific, individual RPM. This ensures proper fuel flow and delivery, even at very high engine RPM.

Yamaha’s V8 XTO Offshore also boasts the highest compression ratio in an outboard – 12.2:1. This means more “bang” from every spark, as well as better efficiency and power.

The new XTO OS propellers for boats and yachts are made to complement the torque potential of the Yamaha V8 425 XTO OFFSHORE Offshore. These new propellers produce more thrust in both forward and reverse, using diameters from 16 to 17⅛ inches. The increased blade surface area is designed for moving big boats and yachts.

The In-Bank Exhaust feature means intake tracks enter the cylinder head from outside of the powerhead, allowing space for exhaust gases to have a direct route to the lower unit and out the propeller hub, improving flow.

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Extreme Toughness and Reliability

In addition to an oversized gearcase, hardened gears, a robust, offshore bracket and motor mounts, the Yamaha V8 425 XTO OFFSHORE outboard also features proven plasma fusion technology for durability and lighter weight.  The outboard also has a two-stage water pump and dual chamber oil pump, each designed to respond to the heavy loads associated with high RPM operation.

Dual overhead, endurance-driven camshafts on each cylinder bank are connected via a self-tensioning chain immersed in an oil bath for accurate valve timing and long life, delivering quiet and precise connection for proper and consistent valve timing. One sprocket belt engagement means a narrower, more compact overall profile.

Carbon-coated shimless bucket-type valve lifters also increase durability, while a dual-chamber oil pump ensures proper oil flow and delivery at every engine speed.

Plasma fusion replaces conventional steel cylinder liners. The micro-textured surface is 60 percent harder than steel and significantly lighter, contributing to increased displacement without increasing the size of the powerhead. The resulting surface also increases fuel economy by decreasing internal friction.
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Spark plugs made from iridium, one of the rarest elements on earth and the second hardest, yield improved throttle response, economy, increased service life and improved power. The new V8 XTO Offshore outboard also features quad thermostats, two thermostats per cylinder bank, for improved flow and better regulation of engine and oil temperature.

A uniquely designed two-stage water pump features a massive rubber water impeller for high pressure and flow. A steel impeller helps provide sufficient water volume even under the most extreme offshore conditions. This configuration provides proper cooling water flow at all RPM and improved temperature control.

Extreme System Integration

The V8 XTO Offshore has integrated electric steering, the first of its kind in any outboard. The integrated steering system has no hydraulic lines or linkages, and responds more quickly than conventional systems to steering inputs. In addition, integrated electric steering means reduced power consumption, clean rigging, and a very orderly bilge area.

The new V8 XTO Offshore outboard also features an Integral Electronic Steering Control Unit that receives signals from the steering cylinder position sensor to carry out joystick and steering operation. Functions integrated into the electric steering system on Yamaha V8 XTO Offshore outboards include: joystick calibration, lever sensor, toe-in/out adjust, joystick thrust, lock to lock, and steering friction set.

Helm Master® and the CL7 Display have also been updated along with the launch of the new XTO Offshore outboard.

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Extreme Convenience, Control and Customer Care

Thanks to an ingenious new exhaust-gas relief system, V8 XTO Offshore propellers bite clean water in reverse, which helps yield reverse thrust up to 300 percent of that developed by Yamaha’s F350. That means easy maneuvering and more control in docking, particularly when the V8 XTO Offshore is matched with Yamaha’s Fully Integrated Boat Control System, Helm Master®.

Boats powered by the Yamaha V8 425 XTO OFFSHORE need go no further than the dock for a lower unit service, thanks to a unique gearcase lubricant exchange system that allows fluid change in the water.  In addition, the V8 XTO Offshore also has great charging capabilities, providing up to 90 amps of total (gross) power and reaches peak net output around 1,500 RPM where it is needed most.

Backed by the best-trained dealer network in the industry and a five-year limited warranty for pleasure use, the Yamaha V8 425 XTO OFFSHORE also has the functionality to facilitate a comprehensive maintenance tracking tool.

All of these benefits—coupled with Yamaha’s reputation for great resale value—assure Yamaha V8 XTO Offshore owners will have an experience second to none.

Yamaha Marine products are marketed throughout the United States and around the world. Yamaha Marine Group, based in Kennesaw, Ga., supports its 2,000 U.S. dealers and boat builders with marketing, training and parts for Yamaha’s full line of products and strives to be the industry leader in reliability, technology and customer service. Yamaha Marine is the only outboard brand to have earned NMMA®’s Customer Satisfaction Index (C.S.I.) Award every year since its inception. Visit YamahaOutboards.com.

This document contains many of Yamaha’s valuable trademarks. It may also contain trademarks belonging to other companies. Any references to other companies or their products are for identification purposes only, and are not intended to be an endorsement.



Engine Type V8 / DOHC / 32 valves / 4 Valves per Cylinder
Displacement 5.6L
Bore x Stroke 96 x 96 mm (3.78 x 3.78 in)
Prop Shaft Horsepower 425hp at 5500 RPM
Full Throttle RPM Range 5000 – 6000 RPM
Alternator Output at W.O.T. 90 Amp Gross, Max
Compression Ratio 12.2:1
Fuel Induction System Direct Injection / Up to 2900 PSI
Weight 432 kg (952 lbs) / 443 kg (977 lbs) / 453 kg (999 lbs)
Recommended Fuel Octane 89
Recommended Engine Oil Yamalube® 4M (See owner’s manual)
Recommended Fuel Filtration Yamaha 10-Micron Fuel / Water Separating Filter (external)




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