Yamaha Four Stroke 425HP Outboard Engine

The massive 5.6 Litre, 32 valve, direct fuel-injection, four-stroke engine delivers enough power to push large and heavy offshore boats. The self-tensioning chain immersed in an oil bath ensures quiet, maintenance free and consistent valve timing.

This industry first ‘steer-by-wire’ system uses an electric motor to directly move and secure the outboard, without any hydraulics or electric pump. This delivers very fast, precise, leak free and maintenance-free steering – that uses less power and is packaged in a clean rigging set-up.

The fully integrated power system creates a truly effortless boating experience. The system combines integrated electric steering, ‘drive-by-wire’ throttle controls, Yamaha’s premium CL7 multifunction display and Helm Master joystick docking and positioning controls.

This powerful three winding, three phase charging system generates up to 90 Amps of electrical power. Additionally, 55 Amps of power can be generated while idling. This high output alternator enables a stable supply of power for running a wide array of electrical devices.

First four-stroke outboard to use direct fuel injection in the outboard industry. A three stage fuel pump system sprays fuel at high pressure directly into the combustion chamber, resulting in better fuel burn, more power and improved fuel efficiency.

The draining and replacement of the lower unit gear lubricant can occur while the boat is docked on the water, making the servicing of larger boats easier, quicker and cheaper.

By designing the cowling in separate, easily removable parts - getting to specific sections of the outboard for servicing is now quicker and easier. This new cowling design also makes it possible to service larger boats while they are docked on the water.

The hydrodynamically designed, oversized gear case enables higher maximum speeds and greater stability when turning. The high quality marine grade stainless steel components and hardened gears have been designed to handle extreme loads and highly corrosive marine environments.

The plasma fusion process creates a cylinder wall surface that is 60% harder than steel, removing the need for conventional steel cylinder sleeves. This significantly reduces weight, improves fuel efficiency and increases the engine capacity, resulting in an improved power-to-weight performance.

Blade slippage is decreased significantly when in reverse due to the exhaust gases being ducted through a ‘relief’ bypass located above the anti-cavitation plate. This improves braking capacity and reduces vibrations through the boat.