The Cox 350, the world’s most powerful diesel outboard, is now certified by the US EPA, a first for a diesel engine of this size.

Engine manufacturer Cox Marine has reached a decisive milestone: its 350 hp V8 engine has successfully obtained U.S. EPA Tier III certification for commercial and recreational applications. This certification enables the British brand to open up its order book in anticipation of the production launch in August.

The new 350 hp V8 is a variant of its V8 Diesel outboard architecture already used on other power ratings. Presented at the Miami International Boat Show in February 2024, the 350 V8 is the latest addition to Cox Marine’s range of Diesel outboard engines. Built on the robust V8 architecture, it continues the legacy of the 300 hp twin-turbo V8 unveiled by the company in 2018.
Diesel outboards, a growing market for commercial applications
The mission of the U.S. Environmental Protection Agency (EPA) is to protect human health and the environment. Cox Marine’s 350 V8 diesel outboard complies with evolving emission standards, and meets the stringent requirements necessary to obtain this mandatory approval.
A decision that Cox Marine has been waiting for, as Gavin Wesson, the company’s CEO, explains: “Obtaining EPA Tier III recognition is an important step that gives us the green light to launch production and take orders for this eagerly awaited engine. The 350 V8 is a game-changer for the marine industry, offering optimal fuel efficiency, power, safety and weight, and efficiently powering large-displacement vessels in the recreational and commercial sectors.”

Obtaining EPA Tier III certification confirms Cox Marine’s progress in this industry and its determination to develop diesel technology for large outboard engines. In particular, this should enable the brand to respond to calls for tender in the military or commercial sectors, where gasoline engines are now prohibited.
The order book for the 350 V8 is now open, with production scheduled to start in August 2024.
source:boatnews