AX300 Diesel Outboard
Built for operators who won’t accept compromise. Unmatched reliability, efficiency and precise handling in all conditions, combine to offer a diesel outboard system for those who demand more. Launching 2026.
The AX300 Diesel’s 3L V6 turbo-charged diesel powerhead delivers up to 50% better fuel efficiency, 27% lower CO₂ emissions, and higher torque than comparable 300hp petrol outboards.
From Day 1 of our design programme, we knew that operators needed an outboard system that had the durability of inboard diesel systems but the flexibility and performance of an outboard. Every element of our design, from seals, to gears, to electronic systems is designed to last 5,000 hours under a defined commercial duty cycle.
Caudwell Marine’s patented AXIS Drive integrated steering system combined with our contra-rotating propellers delivers precise handling, outstanding performance and ultra-efficient power transfer at any speed.
With service intervals every 250 hours and the first major service at 750 hours, the AX300 Diesel keeps you on the water longer. An easy-access service hatch designed into our cowling makes routine checks and in-water maintenance fast and simple. The first time you will need to service your vessel out of the water will be at 750 hours.
AX300 Diesel specification highlights
ENGINE TYPE
3L V6 Turbocharged Diesel
PEAK POWER
290HP
PEAK TORQUE:
72% higher than typical 300 hp petrol outboard
TRANSMISSION
Dual electro-hydraulic clutch (developed in partnership with ZF)
COOLING SYSTEM
High-efficiency closed-loop glycol cooling system
WEIGHT
Approx. 500kg – dependant on spec
EMMISIONS CERTIFICATION
The AX300 Diesel is certified the following marine standards: EPA Tier III, IMO Tier II, RCD2 and UKCA
Download the full AX300 DIESEL specification sheet
AX300 Diesel advantages
The AX300 Diesel is built to last. Tested for thousands of hours in real-world conditions, we have pushed testing to the limits to ensure strength and reliability when it matters most. From deep to shallow water, fresh water to highly saline conditions, from -25C to 45°C ambient conditions matched with extreme water temperatures from freezing to up to 38 degrees C.
Tested across a wide variety of vessels, environmental conditions and duty cycles, the AX300 Diesel consistently delivers outstanding fuel economy. Under typical commercial duty cycles the AX300 Diesel uses 35 litres of fuel per hour.
Wherever you operate, our team of product and application specialists and growing global network of local experts combine to provide you with the highest level of technical support. For complete confidence, our dedicated customer service team is on hand for assistance as you need it.
Every aspect of the AX300 Diesel is engineered for precision handling. Our transmission system, developed with our partners at ZF, delivers smooth gear changes, even under load, while our patented AXIS Drive Integrated Steering allows engines to be mounted closer together for improved stability and agility. Combined with dual contra-rotating propellers, the result is sharper, more agile manoeuvring, and with Caudwell Marine’s intuitive Vessel Control System at the helm, operators gain total command, safer operation, and complete confidence at any speed.
Quick access cowling and an engine design which considers service as well as performance, provides longer service intervals and keeps you on the water for longer. Our hinged service hatch makes routine checks simple, while 50 and 250-hour services can even be done in the water. With major servicing only required at 750 hours, downtime is reduced, saving valuable time and cost.
From a high-efficiency closed-loop glycol cooling system to a dry-sump oiling design, the AX300 Diesel is engineered to protect against wear and maximise reliability. The 60-degree mounting of our powerhead delivers better balance and power transfer, proving that every detail has been optimised for performance and longevity.
Our custom-built Vessel Control System (VCS) puts complete command at your fingertips. Designed for ease, comfort, and versatility across all vessel types, it delivers an exceptional range of features as standard. With NMEA2000 connectivity for seamless integration, the Caudwell Marine VCS ensures intuitive, reliable control of your propulsion system – so every journey begins with smarter safety and effortless confidence.
Find Out How the AX300 Diesel Will Work for You
Interested in learning how the AX300 Diesel could work for your operation? Enter an email address below and you’ll receive an email asking about your vessel and your typical operations. We’ll then be in contact to provide a personalised look at how the AX300 Diesel Outboard could perform for you. Get clear insight into expected speed, fuel efficiency and handling, so you can have total confidence in the advantages for you.
Our support team are here to help
Whether you would like to join our growing global distribution network or find out more about the technical specifications of the AX300 Diesel and how it will perform on your vessel, get in touch with a member of our support team today and we will be delighted to help.
engineered for the toughest marine environments
What our PARTNERS say
“ZF has developed a highly sophisticated twin-clutch transmission system that seamlessly integrates with Caudwell Marine’s purpose-built turbo-charged V6 diesel. Together with Caudwell Marine, we are very confident that we will deliver a product that exceeds the expectations of marine professionals and commercial operators alike.”
Germany
“We are pleased to be working with Caudwell Marine as a supplier because of their commitment to innovation, quality, and performance in marine engineering. Their expertise and forward-thinking approach align well with our values and goals, making them a trusted partner in delivering exceptional solutions to our customers.”
Italy
“Over the past two years, we have greatly valued our association with Caudwell Marine and the reliability of their outboard technology. Being the first external user worldwide has given us the opportunity to experience the advantages first-hand, and we are proud to continue this partnership”
Dubai, UAE