Cummins
EPA Tier 3 Marine Propulsion Engines
Selecting a Cummins EPA Tier 3 engine offers a strategic balance for owners who prioritize mechanical simplicity and long-term durability without the complexity of modern "after-treatment" systems. The primary draw of a Tier 3 engine is that it achieves emission compliance through in-cylinder technology (advanced combustion and high-pressure common rail fuel systems) rather than external components like Selective Catalytic Reduction (SCR) or Diesel Particulate Filters (DPF).
For Recreational Use: Owners of luxury yachts and sportfishers benefit from a quieter, smoke-free experience compared to older Tier 1 or 2 engines. The electronic controls provide precise throttle response and better fuel economy for long-range cruising.
For Commercial Use: In workboats or fishing vessels, Tier 3 engines are prized for their uptime. Because they don't require Diesel Exhaust Fluid (DEF), there is one less consumable to manage at sea and fewer electronic sensors that could potentially trigger a "limp mode" in remote locations.
QSB 5.9
Power: 230 – 480 hp
Torque: 510 – 942 lb-ft
QSL 9
Power: 290 – 410 hp
Torque: 1064 – 1162 lb-ft
QSB 6.7
Power: 230 – 550 hp
Torque: 720 – 1250 lb-ft
QSM 11
Power: 300 – 715 hp
Torque: 1160 – 1750 lb-ft
QSC 8.3
Power: 490 – 600 hp
Torque: 1327 lb-ft
QSB 6.7 Slimline
Power: 355 – 425 hp
Torque: 720 – 1250 lb-ft