Yamaha 425 HP V8 Engine

Yamaha 425 HP V8 5.6L XTO Outboard

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. McMichael Yacht Yards & Brokers is an authorized Yamaha dealer. With a legendary 97% reliability, they’re one of the most trusted outboard brands. Yamaha combines reliability, durability and long range fuel economy throughout their award-winning outboard engine line.

Boats Powered by this Engine: 2019 Regulator 41 

Award-Winning 5.6L V8 HP Outboard

With impressive stats such as 12.2:1 compression ratio for impressive fuel economy and power, industry firsts such as an electric steering system, it’s purpose-built for extreme power, durability, control and reliability.

  • NEW Phase Angle Control Charging System* an award-winning industry first
  • 425 hp on less-expensive 89-octane gasoline
  • Compatible with Helm Master® EX
  • Prop Shaft Horsepower:
    425hp at 5500 rpm
  • Displacement:
  • Full Throttle RPM Range:
    5000 - 6000 rpm
  • Starting System:
  • Gear Ratio:
  • Alternator Output at WOT:
    100 Amps
  • Weight:
    952 - 999 lbs
  • Shaft Lengths:
    25", 30", 35"
  • Recommended Fuel:
    Octane 89
  • Power Trim:
  • Engine Type:
  • Warranty:
    5-Year Limited
  • Fuel Induction System:

System Integration

Digital Electric Steering

The XTO responds quicker to steering inputs because it contains a digital electric steering motor, which directly receives signals form the electric helm to the integrating steering control unit.

Helm Master® EX

Helm Master® integrated boat control system offers greater control with Set Point™ and CL7™ Display

Power And Performance

Direct-Injection Four Stroke

Maximize power and efficiency by spraying fuel at high pressure directly into the combustion chamber.

Exclusive Fuel System

A three-stage low-medium-high pressure fuel pump system works, in part, due to two independent, rpm-activated fuel pumps in the Vapor Separator Tank. This unique five-ump system creates an unprecedented fuel injection pressure of up to 2900 PSI to further maximize atomization and efficiency.

In-Bank Exhaust

Intake tracks enter the cylinder head from the outside of the powerhead. This gives exhaust gases room for a direct route to the lower unit and out through the propeller hub, streamlining the powerhead and improving flow.

XTO (SDS) Propellers

With diameters from 16 to 17 1/8 inches, 15 to 27-inch pitches and increased blade surface, XTO propellers complement the torque potential of our V8 XTO Offshore. They also contribute to greater overall thrust.

Endurance-Driven Camshafts

The XTO features dual overhead camshafts that are each connected via a self-tensioning chain immersed in an oil bath and utilize one-sprocket belt engagement. This ensures quiet, precise valve-timing, compact design, low maintenance and long life.

Two-Stage Water Pump

This unique design ensures proper cooling water flow at all RPMs and improved temperature control. It features a massive rubber water impeller for high pressure and flow, and a steel impeller that helps provide sufficient water volume, even under the most extreme offshore conditions.

Maintenance Videos