A New Generation in Diesel Technology

The CXO300 is a new generation of diesel power. It is a light-weight and robust marine propulsion option that requires 25% less fuel but offers you a 480 torque. Designed to last 3x longer than a gasoline equivalent, this diesel outboard combines exceptional performance, with the reassurance of proven V8 diesel technology.

Designed for purpose

The CXO300 diesel outboard has been designed and built specifically for marine use – the first of its kind. As one of the most powerful diesel outboards 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. The diesel outboard motor takes standard pump diesel, has a standard outboard fitting layout, and is compatible with all Seastar EPS steering.

The CXO300 is commercially rated, giving you industry assurance, but also has a recreational warranty of 5 years and a commercial warranty of 18 months or 1500 hours.

CXO300 Spec

Engine DesignationCXO300
Propeller shaft power, kW (hp)224 (300)
Engine propping speed, rpm3700-4000
Displacement, L ( (266)
Weight, kg (lb)393 (866)
Number of cylinders8
Bore/stroke, mm (in.)84 (3.3) / 98.5 (3.9)
Compression ratio16:1
Ratio 1 (Propeller speed)1.23:1 (3259)
Ratio 2 (Propeller speed)1.46:1 (2739)
Peak torque, Nm ( (479)
Shaft Length, inch(mm)25”(635) / 30”(762) / 35”(889)
Emission complianceEPA 3, IMO 2, RCD 2
RatingLight-duty commercial
Trim range-4° to +16°
Tilt range71°
Gear Oil SpecSAE 80W90, API GL-5
Powerhead Oil SpecMin standard – fully synthetic API CI-4/ SAE 10W40 or 5W40
Propeller spline spec1.25” shaft / 19 tooth
Colour optionsBlack / 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 just 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 you don’t have to miss out on that fishing weekend that 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.


If you have any further questions about our diesel outboard, please get in touch with our team, who will be happy to provide advice and guidance. We also run demonstrations of the diesel outboard motor, so that you can see it in action. To register your interest please fill in our demonstration form and we’ll get back to you ASAP.

Book a Demo