Isuzu Marine

Engines • Parts • Maintenance • Repairs • Rebuilds

New Zealand’s exclusive Isuzu Marine dealer.

Shaw Diesels provides sales, genuine spare parts and ongoing support for the Isuzu range of purpose-built commercial marine engines.

Isuzu Marine engines have been powering commercial fishing boats, ferries, tugs, charter vessels and workboats since 1947. Here at Shaw Diesels we offer the full range of genuine Isuzu Marine propulsion engines, backed by parts and expert service and support from our Auckland and Christchurch branches.

Made for the harshest marine environments.

Every Isuzu Marine engine is engineered from the ground up for the marine environment.

They feature indirect seawater cooling via heat exchangers, water-cooled wet exhaust systems that limit engine room heat and reduce fire risk, spark-arrested alternators, corrosion-resistant starters with epoxy coating and sealed casings, and dual-diaphragm fuel pumps with bleed-off lines to prevent fuel spill.

Every engine comes with SAE-standard flywheel housing for direct marine gearbox connection, and is rated to specific marine duty cycles — from light duty through to continuous heavy-duty commercial operation. All models are IMO Tier II emissions compliant.

With a genuine Isuzu Marine engine you know that every component is factory-specified for saltwater operation. No compromises, no aftermarket adaptations, and full factory support.

From 135 to 720 horsepower.

With ten models across seven engine platforms, there’s an Isuzu Marine engine that’s right for your vessel.

The Isuzu Marine propulsion range covers four and six-cylinder engines across displacements from 3.05 to 15.68 litres. The smaller four-cylinder models (UM4JG1TCX and UM4BG1TCX) deliver 135 to 197 hp, ideal for launches, small commercial vessels and coastal workboats.

The six-cylinder range opens up from the UM6BG1 series at 226–285 hp through to the UM6HE1TCX (345 hp) and UM6SD1TCX (374 hp) for larger commercial fishing vessels, charter boats and ferries. At the top of the range, the UM6WG1 series offers four power ratings from 505 to 720 hp, delivering serious displacement power for tugs, dredges, large ferries and heavy commercial operations.

Every model is designed for high torque at low RPM, enabling large, efficient propellers that reduce cavitation and underwater noise. These are engines built for vessels that push through the water, not over it.

Built for the long haul.

Isuzu Marine engines are famous for their longevity, in even the toughest environments.

It’s all thanks to some really clever design that’s the result of nearly 80 years of pioneering enhancements (such as ceramic glow plugs and Japan’s first common-rail marine diesel engine).

Chromed dry-fit cylinder liners without O-rings eliminate the liner pitting that plagues conventional designs, extending engine life significantly. Isuzu’s swirl-type combustion chambers optimise the air-fuel mix for efficient, clean burning at every load point.

The high-torque, low-RPM design philosophy means the engines don’t need to work hard to deliver serious power. Lower engine speeds reduce wear, lower fuel consumption and allow the use of large-diameter propellers that convert more power into forward motion.

It all adds up to a quieter, more fuel-efficient vessel that covers more distance on less diesel.

Every component is made for marine.

Every genuine Isuzu Marine engine comes factory-equipped with marine-specific components as standard.

Indirect seawater cooling — heat exchanger system designed for continuous saltwater operation
Water-cooled wet exhaust — reduces engine room temperature and fire risk
Spark-arrested alternator — extra plates and screens for fire prevention in enclosed engine spaces
Corrosion-resistant starter — epoxy-coated and sealed for the marine environment
Dual-diaphragm fuel pump — bleed-off lines prevent fuel spill into the bilge
SAE flywheel housing — direct connection to marine gearboxes (MGN series available)
Zinc anode protection — factory-fitted galvanic corrosion protection
Marine instrument panel — complete monitoring and control as standard
IMO Tier II compliant — meets international maritime emissions standards

Options include heat exchanger or keel cooling, Nikko marine transmissions, vibration isolators, extended wire harnesses, dual station panels, keel coolers and front PTO (capacity varies by model).

Sales, parts and service across New Zealand.

Shaw Diesels is your single point of contact for Isuzu Marine engine sales, genuine parts and ongoing service support throughout New Zealand.

As the exclusive NZ dealer for Isuzu Marine, we handle everything from initial engine selection and specification through to delivery, commissioning and ongoing maintenance. Our diesel engineers work across the full Isuzu marine range, from the compact four-cylinder models through to the 720 hp UM6WG1TCX.

We stock genuine Isuzu marine parts in New Zealand and have access to the broader Isuzu Power Solutions network of approximately 70 locations across Australia and New Zealand for specialist components. For operations that depend on their vessels, we offer scheduled maintenance programmes and responsive service support.

Based in Auckland and Christchurch, with service capability across New Zealand, our team is where you need us — whether you’re fitting out a new build, repowering an existing vessel, or keeping a working fleet on the water.