C12 Propulsion Engine

C12 Propulsion Engine

Cat® C12 Diesel Marine Propulsion Engines, with ratings of 340-490 bhp (254-366 bkW) at 1800-2300 rpm, meet IMO II emission standards with the exception of the 497 mhp (490 bhp) rating at 2300 rpm which meets IMO I emissions standards. The C12 takes full advantage of the electronically controlled unit injection fuel system, resulting in an environmentally friendly engine with outstanding performance and fuel economy. There is also a wide range of optional equipment available to meet the needs of your marine commercial or pleasure craft application.

Power Rating

Power Range
340-490 bhp (254-366 bkW)

Engine Specifications

Speed Range
1800-2300 rpm
Rotation (from flywheel end)
In-line 6, 4-Stroke-Cycle Diesel

Dimensions & Weights

Dry Weight
Maximum Length
Maximum Height
Minimum Width

Standard Equipment

  • Air Inlet System
    • Aftercooler - sea water; corrosion resistant, Air Cleaner/Fumes Disposal (closed system), Turbocharger, Jacket Water Cooled
  • Control System
    • Electronic governing, Cold mode start strategy, Power compensation for fuel temperature, Programmable low idle, Electronic diagnostics and fault logging, Engine and transmission monitoring (speed, temperature, pressure), Fuel/air ratio control, Emergency stop switch (A&B ratings only)
  • Cooling System
    • Thermostat and housing, Jacket water pump; gear driven, Sea water pump; rubber impeller; self-priming; gear-driven, Integral heat exhanger/expansion tank; removable tube bundle; replaceable copper-nickel tubes, Keel cooling - combined circuit (includes pipe thread flange kit)
  • Exhaust System
    • Watercooled Manifold & Turbocharger
  • Flywheels & Flywheel Housings
    • Flywheel; SAE No. 1; 113 teeth, Flywheel housing; SAE No. 1 (10 degree slant pad), SAE standard rotation
  • Fuel System
    • Fuel filer; RH service on Port; LH service on Starboard, Fuel transfer pump, Fuel priming pump, Flexible fuel lines
  • Instrumentation
    • Service meter, electric
  • Lube System
    • Crankcase breather, Oil cooler, Oil filter; spin-on; RH service on Port; LH service on Starboard, Oil filler, Dipstick; RH service on Port; LH service on Starboard, Oil pump; gear driven
  • Mounting System
    • Front support
  • Power Take-offs
    • Hydraulic pump drive; SAE A; 11 tooth spline, 57 ft-lbs max torque; counterclockwise as viewed from the rear of hte engine looking into the pump drive and turns 1.41 x engine speed, Crankshaft pulley; 345 mm (13.6 in) single groove; 15.88 mm (.63in) width
  • Protection System
    • Shutdown; electronic; 12 or 24 volt; energized to run
  • General
    • Vibration damper, Lifting eyes, RH or LH service options, Literature, Variable engine wiring, Upper rear-facing customer wiring connector and ECAP connection, Electronic installation kit (connectors, pins, sockets)

Optional Equipment

  • Air Inlet System
    • Low Profile Air Inlet Line, Shield (Air Inlet Line)
  • Charging System
    • Charging Alternators, Voltmeter Guages, Voltmeter Guage Mounting, Alternator Mounting Group
  • Cooling System
    • Sea Water Pump, Coolant Recovery Tank, Flange Kit
  • Exhaust System
    • Flexible Fitting, Elbow, Dry Elbow, Watercooled Elbow, Exhaust Connection, Exhaust Outlet Pipe, EXH Outlet Flange, Rain Cap, Muffler
  • Fuel System
    • Fuel Cooler, Fuel Connections, Primary Fuel Filter, Primary Fuel/Water Separator
  • Instrumentation
    • OEM Wiring Harness, Engine to Engine Harness, Digital Tachometer, Tachometer Mounting, Magnetic Pickup, RH 4 Hole Instrument Panel, LH 4 Hole Instrument, Marine Power Display System, Marine Power Display Unit (for additional monitoring stations), Marine Power Display Bracket, Wiring Group, Transmission Sensors
  • Lube System
    • Manual sump pump, Transmission oil cooler
  • Mounting System
    • Vibration Isolators
  • Power Take-offs
    • Crankshaft Pulley, Front Stub Shaft, Front Stub Shaft & Pulley
  • Starting System
    • Air Pressure Regulator, Air Start Silencer, Start Switch, Jacket Water Heater, Battery sets (24 volt - dry)
  • General
    • Wiring Harness Removal, Belt Guard - Alternator, Belt Guard - Alternator Pulley, Filter Cover Kit
  • Packing
    • Overseas Preservation, Engine Protective Cover, Storage Preservation, Export Packing