Yamaha V8 425 XTO locks in Perth boat show for Australian arrival

The Yamaha V8 425 XTO has locked in a September 24 Australian launch.

The 5.6-litre V8 is aimed squarely at those needing more big-boat shove than a V6 can deliver. It will make its official Australian debut at the 2018 Perth International Boat Show, which runs from September 21-24.

boatsales.com.au believes that a number of commercial clients have already placed orders for the big banger, with private buyers showing strong interest in having the biggest and the best outboard hanging from their vessel’s transom.

Yamaha has also released pricing for the engine; $62,000 before you add on the prop, controls and gauges.

The V8 425 XTO is the most powerful outboard engine that Yamaha has ever produced, delivering an officially rated 425hp/312.6kW at 5500rpm. It’s also the most powerful outboard from a mainstream brand.

There is, however, more power out there. Seven Marine, which had engines on display at this month’s Sydney International Boat Show, uses a heavily modified, supercharged 6.2-litre V8 to produce outputs up to 627hp, delivered to the water via twin-prop systems.

Yamaha’s V8 was developed with North America firmly in mind; it’s a key market for outboard motors worldwide, and the marine engine maker said sales of large outboard motors there remained “healthy”.

The growing popularity of outboard systems is particularly noticeable for boats measuring more than 30 feet, which are starting to move away from traditional inboard and sterndrive systems, it said.

Yamaha says its big outboard can offer advantages in terms of speed (the V8 is optimised to drive large props on big boats) fuel economy, maintenance, and yielding more useable space onboard.

The engine is also Yamaha’s first to use a fully integrated power generation system, and the first to use direct fuel-injection to deliver precise amounts of fuel into the cylinders to help maximise either performance or fuel economy. Other cutting-edge technology includes sleeveless cylinders and iridium spark plugs.

It is also fully contained, with an internally mounted fly-by-wire steering system replacing traditional external electric or hydraulic systems. Yamaha has also given thought to ease of maintenance, with a separate gear lubrication reservoir allowing oil changes while the craft is still on the water.

The Yamaha V8 425 XTO will also be on show at the Brisbane Boat Show, which opens today.

SPECIFICATIONS
Engine type: Four-stroke, 32 valve twin-cam direct injection V8
Bore x stroke: 96 x 96 (mm)
Displacement: 5559cc
Maximum RPM: 5000-6000rpm
Fuel management: EFI
Ignition: TCI
OEDA emission rating: 3
Lubrication system: Wet-sump
Alternator output: 90 amp
Gear ratio: 1.79 (25/14)
Starter system: Electric
Operation method: Internal steer-by-wire
Trim and tilt: Power
Digital gauges: Optional
Command Link gauges: Optional
Transom height (mm): 640/U: 767/E: 894
Dry weight (kg): 442/U: 453/E: 463