Outboard Diesel Attains EPA Tier 3 Approval

Publish date:

It’s full steam ahead for Cox Powertrain.

The U.K.-based company said that its most powerful offering — a 300-hp, diesel-powered outboard — has achieved full Tier 3 approval from the United States Environmental Protection Agency.

The EPA approval applies to both commercial and recreational applications.

Cox premiered the CXO300, a 300-hp, oil-burning powerplant back in 2018 at the Fort Lauderdale International Boat Show with a twin setup on a 34-foot Intrepid. It’s claims are impressive— 25 percent better range and 100 percent higher torque versus its 300-hp gas counterpart.


Production was delayed — it was said to be “imminent” at last year’s FLIBS — but finally kicked off last month at the company’s Shoreham-by-Sea facility, with shipments expected to be shipped to stateside dealers sometime this month.

“We developed a diesel engine with a much lower carbon footprint than an equivalent gasoline outboard,” said Cox global sales director Joel Reid in a statement. “So far, those who have joined us on sea trials have commented favorably how quiet, smooth and clean the engine is.”

The engines are available in three shaft lengths — 25-inches, 30-inches and 35-inches — are NMEA 2000 compatible and are designed to match industry standards for installation on suitable outboard-powered vessels.

The company has said that pricing on the CXO300 would be around $55,000, which is double the price — roughly — of its gas outboard counterpart.