The World's Most Powerful Diesel Outboard

CXO300 Spec

Engine Designation CXO300
Propeller shaft power, kW (hp) 224 (300)
Engine propping speed, rpm 3700-4000
Displacement, L ( 4.4 (266)
Weight, kg (lb) 393 (866)
Number of cylinders 8
Bore/stroke, mm (in.) 84 (3.3) / 98.5 (3.9)
Compression ratio 16:1
Ratio 1 (Propeller speed) 1.23:1 (3259)
Ratio 2 (Propeller speed) 1.46:1 (2739)
Peak torque, Nm ( 650 (479)
Aspiration Twin-turbo
Shaft Length, inch(mm) 25”(635) / 30”(762) / 35”(889)
Emission compliance EPA 3, IMO 2, RCD 2
Rating Light-duty commercial
Trim range -4° to +16°
Tilt range 71°
Gear Oil Spec SAE 80W90, API GL-5
Powerhead Oil Spec Min standard – fully synthetic API CI-4/ SAE 10W40 or 5W40
Propeller spline spec 1.25” shaft / 19 tooth
Colour options Black / White


Technical Description

Engine block and head

  • 60 degree V8
  • Aluminium alloy block, heads and ladder frame
  • Quad camshafts, four valves per cylinder

Engine mounting

  • Standard outboard fitting layout
  • 6-bolt mounting with multi-hole adjustment
  • 30″ transom spacing (28.5″ with steering limits)

Fuel system

  • Electronically controlled high-pressure common rail injection
  • On-engine fuel filtration and cooling

Air inlet and exhaust system

  • Twin turbochargers with electronic boost control
  • Water-to-air charge cooling
  • Air filters with replaceable inserts


  • 90-degree spiral bevel gear drive
  • All outboard offer standard and counter rotating capability, programmable through the ECU

Cooling system

  • Thermostatically regulated raw water cooling
  • Solid impeller low-maintenance water pump

Oil system

  • Closed crankcase ventilation 

Electric system

  • Drive-by-wire power and shift control
  • 12V electrical system
  • 100A flywheel-integrated marine alternator
  • Automatic integrated fuses


  • Maximum propeller diameter 16″
  • 19 tooth 1.25″ propeller spline


  • Seastar electronic throttle
  • Seastar joystick
  • Coastkey Keyless key fob / wireless MOB technology
  • Compatible with NMEA 2000
  • Murphy Powerview displays – 4.8”/7”/10”/12” screen sizes
  • Compatible with all Seastar EPS steering

Choose your CXO300

Less Fuel
Longer Life

Retrofit Compatibility

Although the first of its kind, as the most powerful diesel outboard brought to the market, the CXO300 has been developed to be compatible with existing industry standards – making it as easy to install on a wide range of vessels as any gasoline outboard.


Standard pump diesel


NMEA 2000 compatible


Transom same as current standard


Off the shelf


Compatible with all major brands

redefining standards

When purchasing a Cox diesel outboard you are buying more than an engine, you are acquiring a new level of service and care that comes standard with all our products. We have defined service standards to ensure you don’t lose a week’s worth of revenue, or that fishing weekend you have been planning for weeks because your engine is down. We offer an engine substitution programme and a true 24/7 customer service to ensure there is always somebody available to assist our customers no matter where in the world, no matter what time.

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