yamaha 425 hp outboard
2019 YAMAHA 425 HP XF425XSA Outboard Motor
The XTO Offshore is the result of years of collaboration with top boat designers, and has been built from the ground up to provide the ultimate in power and efficiency offshore. With impressive stats such as the highest compression ratio on the water, industry firsts such as an electric steering system, and engineering touches such as iridium spark plugs and quad thermostats, it’s purpose-built for extreme power, durability, control and reliability.
Yamaha has built an enviable reputation for building highly reliable, technology driven, big horsepower engines. We have now taken this to the extreme with the release of the all-new V8 425 XTO (Extreme offshore) outboard.
This beast of an engine has been designed from the ground up to deliver maximum power and thrust. Powered by a big bore, 5.6 litre, naturally aspirated engine, the XTO Offshore opens up a whole new class of large outboard driven boats, delivering a more reliable, fuel efficient and premium quality engine solution.
The XTO Offshore is not only our most powerful outboard, it is also our most technologically advanced, with the introduction of Yamaha’s first fully integrated power system.
This system combines a revolutionary fully integrated electric steering system, with our premium CL7 multifunction display, advanced ‘drive-by-wire’ throttle controls and Helm Master joystick docking and positioning controls – creating a truly effortless boating experience.
Other key features include an in-water gear lube change system, oversized rugged gear case and hardened gears, massive 90 Amp power-generation system and large diameter XTO OS high thrust prop.
Presented in a very stylish, compact and powerful looking package, this outboard is sure to be the envy of every boat owner.
- Available in signature Yamaha gray or new pearlescent white
- 425 hp on less-expensive 89-octane gasoline
- Available with Helm Master® with SetPoint™
- Impressive 5-year Limited Warranty, for pleasure use
2019 Yamaha V8 XTO Offshore 425 review
The Yamaha XTO Offshore 425hp arrived late in 2018 to relatively little fanfare in Australia, yet this giant four-stroke outboard is one of the most sophisticated, technologically advanced marine engines ever made. We were fortunate enough to trial a pair of these stunning new outboard engines recently, mounted on a Grady-White Express 330.
Overview of yamaha 425 hp outboard
Marine market trends in the US generally set the tone worldwide, and right now what we can see coming out of America are increasingly bigger outboard engine-powered boats with two, three, and even four or more massive outboards hanging off the transom.
Naturally, outboard engine makers have seen this trend emerging for quite some time and have set about the development of larger engines to suit. After all, it makes more logistical (and financial) sense to rig a big centre or dual console bluewater fishing boat with, say, a pair of 400hp outboards rather than quad 200hp engines.
Only a few years ago, mainstream production outboards (ignoring the low-production, very high cost super outboards from boutique manufacturers such as Seven Marine) topped out at 350hp. Mercury then upped the ante with the arrival of its Verado 400R supercharged six-cylinder outboard engine. Now Yamaha has countered with its own mega-engine, the naturally aspirated 5.6-litre V8 XTO Offshore 425.
As it stands right now, Yamaha builds the most powerful regular production four-stroke outboard among the big four outboard engine makers. There are higher power motors from specialist brands, but the Yamaha V8 XTO Offshore 425 is the biggest “off-the-shelf” outboard engine you can buy from your local dealer.
And what a terrific new engine it is, too, purpose-designed for the marine environment with a range of break-through mechanical and convenience features.
The Yamaha XTO Offshore 425 is a 5559cc V8, twin-cam, 32-valve, four-stroke engine. It was introduced into the Yamaha four-stroke outboard range to compliment the long-running 5.3-litre 350hp model. Both are V8s, but the latest 425hp engine is a completely new design incorporating state-of-the-art features.
Chief among them is the industry first “steer-by-wire” integrated electric power steering system (no pumps or hydraulics), which Yamaha says provides for faster response to steering inputs and better control.
There’s also a clever exhaust gas relief system, whereby the exhaust gases are diverted away from the propellers below 2500rpm so the props can bite cleaner water for more thrust in reverse. Yamaha says the new engine delivers 300 percent more thrust in reverse than the smaller Yamaha F350.
yamaha 425 hp outboard
The Yamaha XTO Offshore 425 is also the first four-stroke outboard to feature high pressure (up to 2900 psi) direct fuel injection (DFI). This, in turn, allows Yamaha to run the highest compression ratio (12.2:1) of any outboard enigne for better fuel efficiency and a stronger, more responsive delivery of power throughout the rev range.
With mountains of DFI-assisted power and torque available from low down in the rev range, this big displacement Yamaha V8 is able to swing purpose designed, larger diameter XTO propellers (equipped with Yamaha’s low vibration Shift Dampener System) to push big boats and heavy loads with ease.
In keeping with the design brief to produce the best, highest thrust big boat saltwater outboard engine, everything about the XTO Offshore 425 is upsized and over-built.
For example, the engine runs an over-sized gearcase with hardened gears. It also has heavy duty motor mounts, a two-stage water pump, dual chamber oil pump, special iridium spark plugs for longer service life, and “plasma-fused” sleeveless cylinders for reduced friction, faster heat transfer and increased fuel efficiency.
A host of other technical innovations are also built into the new Yamaha XTO Offshore 425. You can check online for more details, but key features include a three-stage fuel pump system (with five pumps overall) for precise fuel delivery, an in-bank exhaust system for a more direct, less restricted flow of exhaust gases to the propeller hub, low friction carbon coated lifters, and quad thermostats for regulating engine and oil temperature.
The only downside to the big Yamaha’s rugged, over-engineered construction and high tech design wizardry is that it has come at the cost of engine weight. The lightest model tips the scales at a substantial 432kg – and that’s a dry weight without a propeller and without engine or gearcase oil. By comparison, Yamaha’s F350 V8 weighs 346kg.yamaha 425 hp outboard
The nearest competitor engine to the Yamaha XTO Offshore 425 is Mercury’s supercharged 400R. Whilst this is an older-tech engine with its peak power delivered at higher revs (and rumoured to be replaced soon), it is a featherweight by comparison, tipping the scales at just 303kg for the lightest model.
Having noted the above, the Yamaha XTO Offshore 425 was not designed to be the lightest 400hp-plus outboard on the market, but to be the best outboard for powering large, 10 metre-plus bluewater sport fishing boats and cruisers in dual, triple and quad installations – and to work in harmony with Yamaha’s upgraded Helm Master joystick boat control system.
Price and equipment of yamaha 425 hp outboard
The Yamaha XTO Offshore 425 is available in two standard sizes; extra-longshaft 635mm (25-inch), and ultra-longshaft 762mm (30-inch).
Also available, albeit by special order, is an all-new super-longshaft 889mm (35-inch) model designed for high transomed express cruisers and large fly bridge fishing boats that would traditionally be powered by inboard shaft drive diesel motors.
You can also order your new XTO Yamaha in white, instead of the traditional Yamaha grey, by digging a little deeper in your pocket.
Yamaha has advised that pricing for the XTO starts at $62K for the extra-longshaft, right-hand rotation model plus another $8K or so for required rigging, such as the XTO Electric Helm, Command Link 7 Plus premium digital display, propeller, etc.
This sounds quite pricey initially, but it does include the new integrated electric power steering system that provides effortless steering control, and a cleaner, neater transom with just a single rigging tube.
As noted, the Yamaha XTO offshore 425 is compatible with Yamaha’s latest Command Link Plus 7.0-inch display (and other digital gauges) and the Helm Master joystick control low-speed manoeuvring system for a bit of extra money.
To facilitate multiple engine installations, the XTO 425 has 72.4mm (28.5-inch) mounting centres and can come in right- and left-handed rotation. The engine mounting holes are also identical to the smaller F350, so boaters with the older Yamaha V8s can easily repower with the larger outboard engines.
For ease of servicing the Yamaha XTO Offshore 425 employs a multi-piece cowling to provide access to specific parts of the powerhead. You’ll also find two methods for flushing out the engine at the end of a day’s fishing, and the gearcase oil can be changed whilst the boat is on the water in a marina pen.
Service intervals for the Yamaha XTO Offshore 425 are similar to other four-strokes. After an initial 20 hour/three month service for checks and minor adjustments, the service schedule runs annually or every 100 operating hours.
Yamaha was not specific about the cost to service this big new engine, but the company did say that it should be comparable with its other high-power models.
Some of the other cool engine features include a 90 amp alternator (with an impressive 59 amps available at idle), 73 degrees of tilt so you can lift the engine completely out of the water, a tilt-limit/stop mechanism, a 31-degree wide steering range, Yamaha’s Variable Trolling RPM feature, and more.
Power and performance
The Yamaha XTO Offshore 425’s forte is powering large offshore fishing console boats and cruisers, and this was evident during our test of a pair of these big engines on the back of a Grady-White Express 330. The boat/engine combination performed beautifully on the water, proving swift and agile.
The 432kg base weight of the Yamaha XTO might be of concern on smaller craft with single engine installations, but with big, wide-beam boats such as the Grady-White, engine weight is simply not an issue. In fact, I reckon we could have bolted a third engine on the transom and the hull would still have felt well balanced.
Underway, with 850hp on the transom, the Grady-White Express 330 felt responsive, quick and manoeuvrable. The electric power steering and digital throttle controls were sublime, providing finger-tip control and easy handling.
Through tight turns the purpose designed big-boat, large-diameter Yamaha propellers held a very solid bite on the water with virtually no slip or ventilation.
When I slammed down the throttles on corner exit, the Grady test boat responded with surprising agility, the big Yamahas providing a powerhouse of thrust and torque to surge the big rig forward and onto a top speed of 46.25 knots. For a 10-metre, 6500kg cruiser, that’s really shifting along.
I found the Yamaha XTO Offshore 425s to be smooth, linear in their mid power delivery, and reasonably quiet at modest speeds. Hit the throttles from around 4000 rpm, however, and the engines really open up, the rise in their volume almost commensurate with the test boat’s swiftly gathering forward momentum.
At wide open throttle, I’d have to say that the big Yamahas roar rather than sing. They were certainly louder than I had expected, although we did have two of them on the Grady’s transom, and the sound was likely echoing back from the test boat’s semi-enclosed helm station.
The test boat was not fitted with Yamaha’s Helm Master joystick control system but was nevertheless very manoeuvrable at low speeds due to the very strong reverse gear thrust available from the Yamahas, in combination with the inclusion of a bow thruster.
With regard to fuel economy, Yamaha claims the XTO Offshore 425 is around 10 percent more fuel-efficient than its smaller F350 V8. That’s impressive for a bigger, more powerful engine
- Engine Type: Yamaha XF425XSAXTO Offshore Four Stroke
- Horsepower: 425 hp
- Cylinders: 8 cyl
- Shaft Length: 35″
- Steering: Integrated Electric
- Starter: Electric
- Weight: 999 lbs
- Full Throttle Range: 5000 – 6000 rpm
- Displacement: 5,559cc
- Induction System: Direct Injection
- Warranty: 5 years