Cummins 6BTA 5.9 Marine Engine Guide

Cummins 6BTA 5.9 Marine

The Gold Standard of Marine Diesel Performance and Reliability

Cummins 6BTA 5.9 Marine Engine

Proven Power: The Diamond Series Legacy

The Cummins 6BTA 5.9 is a legend in the marine world, particularly in its "Diamond Series" configurations. This mechanical, 12-valve inline-six is prized for its high power-to-weight ratio and simplicity. Unlike modern electronic engines, the 6BTA relies on a mechanical Bosch fuel system, making it the most reliable choice for sportfishing, commercial work, and classic yacht repowers. At Choate Performance, we build these engines to withstand the relentless load of marine duty, correcting factory weaknesses for a lifetime of service.

5.88 LitersDisplacement
102mm x 120mmBore & Stroke
MechanicalInjection (Bosch P7100)
Turbo/AftercooledAspiration

Identify Your Marine Rating

The 6BTA 5.9 was offered in several distinct horsepower ratings. Identifying your specific CPL (Control Parts List) ensures your replacement engine matches your hull's performance requirements.

Horsepower Rating Common Application Injection Pump Cooling Type
210 HP Trawlers / Displacement Hulls Bosch A-Pump Heat Exchanged / Keel Cooled
270 / 315 HP Express Cruisers / Light Commercial Bosch P7100 Sea Water Aftercooled
330 / 370 HP Sportfish / High Performance (Diamond) Bosch P7100 (Enhanced) Sea Water Aftercooled

Vessel Compatibility

From factory installs to the most popular repowers in the industry, the 6BTA powers the world's most iconic hulls.

Sportfish & Express

  • Cabo 31 & 35 Express 370HP
  • Sea Ray 370 & 400 Sundancer 330HP
  • Tiara 3500 & 3700 Open 370HP
  • Bertram 31 & 33 (Repower) 315HP
  • Ocean Yachts 40 Super Sport 370HP

Cruisers & Trawlers

  • Mainship 30 & 34 Pilot 315HP
  • Albin 28 Tournament Express 315HP
  • Grand Banks Heritage Series 210HP
  • Silverton 351 Sedan Bridge 330HP

Commercial & Patrol

  • Maine Lobster Boats (Various) 370HP
  • Willard Marine RIBs 315HP
  • Water Taxis & Small Ferries 270HP
  • Charter Fishing Vessels 370HP
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The Marine Data Plate

Unlike automotive Cummins engines, Marine 6BTAs have a data plate typically located on the side of the front gear housing. Look for the 8-digit Engine Serial Number (ESN) and the 4-digit CPL number. This is vital to ensure your aftercooler, turbo, and seawater pump configurations match your engine room layout.

Planning a gas-to-diesel repower? Contact our team for technical advice on mounting and transmission matching.

The "Aftercooler" Alert

Neglecting your marine aftercooler is the #1 cause of 6BTA engine failure. Learn how to service your seawater cooling system to prevent catastrophic internal corrosion.

MAINTENANCE GUIDE

Built for the Blue Water

Our remanufactured 6BTA marine long blocks feature upgraded gaskets and precision balancing for smooth, reliable operation offshore.


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Speak with a Marine Specialist: 901-553-9847