What Is the Yanmar 6LY Marine Engine?
The Yanmar 6LY Marine Engine is a well-established inline six-cylinder marine diesel family used in recreational, cruising, performance, repower, and light-commercial vessels.
An important point when sourcing Yanmar 6LY marine engine spare parts is that "6LY" covers several generations. The older mechanical 6LY engines and newer electronically controlled 6LY engines do not all use the same fuel-system and control components.
The family includes engines such as:
- Yanmar 6LYA-STP
- Yanmar 6LY2A-STP
- Yanmar 6LY3-STP
- Yanmar 6LY400
- Yanmar 6LY440
The current 6LY-CR generation consists of the 6LY400 and 6LY440. Yanmar describes these as fourth-generation 6LY engines using Denso common-rail fuel injection and electronic vessel controls.
Alfa Marine Spare Parts supplies OEM, genuine, aftermarket, and remanufactured Yanmar 6LY marine engine spare parts for scheduled maintenance, repairs, fuel-system service, cooling-system repairs, major component replacement, rebuilding, and overhaul requirements.
Yanmar 6LY Technical Information
Because the 6LY family covers different generations, technical specifications should always be connected to the exact engine model.
Specification6LY400 / 6LY440Engine TypeMarine dieselCycleFour-strokeCylinders6ArrangementInlineDisplacement5.813 LBore106 mmStroke110 mmFuel SystemDenso Common RailCombustionDirect InjectionAspirationTurbocharged & IntercooledRated Speed3300 rpmControlsElectronicDry Weight Without GearApprox. 585 kg
Yanmar rates the current 6LY400 at 294 kW / 400 mhp and the 6LY440 at 324 kW / 440 mhp, both at 3300 rpm.
What Is the Difference Between Older and Newer Yanmar 6LY Engines?
This is one of the most important questions when ordering parts.
The 6LY family has evolved considerably.
For example, the 6LY2A-STP is a mechanically controlled engine using direct injection with an inline injection pump. Yanmar lists it at 324 kW / 440 mhp at 3300 rpm.
The later 6LY3-STP uses electronically controlled injection.
The current 6LY400 and 6LY440 use a Denso common-rail system and electronic controls.
This means you should never order a component simply by saying:
"I need a part for a Yanmar 6LY."
The complete engine model and serial number are important.
Yanmar 6LY400 Marine Engine
The Yanmar 6LY400 is part of the current 6LY-CR generation.
Key specifications include:
- Rated output: 294 kW / 400 mhp
- Rated speed: 3300 rpm
- Cylinders: 6 inline
- Displacement: 5.813 L
- Bore × stroke: 106 × 110 mm
- Fuel system: Denso common rail
- Aspiration: Turbocharged and intercooled
- Controls: Electronic
- Dry weight without gear: Approximately 585 kg
Yanmar also lists the 6LY400 as HVO-approved.
Yanmar 6LY440 Marine Engine
The Yanmar 6LY440 shares the current 6LY-CR architecture but provides higher rated output.
Key specifications include:
- Rated output: 324 kW / 440 mhp
- Rated speed: 3300 rpm
- Cylinders: 6 inline
- Displacement: 5.813 L
- Bore × stroke: 106 × 110 mm
- Fuel system: Denso common rail
- Aspiration: Turbocharged and intercooled
- Controls: Electronic
- Dry weight without gear: Approximately 585 kg
Yanmar also lists the 6LY440 as HVO-approved.
Yanmar 6LY2A-STP Marine Engine
The Yanmar 6LY2A-STP is an earlier mechanically controlled member of the family.
Yanmar specifies:
- Rated output: 324 kW / 440 mhp
- Rated speed: 3300 rpm
- Displacement: 5.813 L
- Cylinders: 6
- Bore × stroke: 106 × 110 mm
- Combustion: Direct injection
- Fuel system: Inline injection pump
- Aspiration: Turbocharged and intercooled
- Controls: Mechanical
- Dry weight without gear: Approximately 535 kg
This distinction matters when sourcing injectors, injection pumps, control components, sensors, wiring, and associated fuel-system parts.
Yanmar 6LY3-STP Marine Engine
The 6LY3-STP represents another stage in the development of the 6LY family.
Yanmar lists it with:
- 324 kW / 440 mhp
- 3300 rpm
- 5.813 L displacement
- 6 cylinders
- 106 × 110 mm bore and stroke
- Electronically controlled direct injection
- Turbocharging and intercooling
This is another reason why the exact 6LY generation should be identified before selecting spare parts.
What Fuel System Does the Yanmar 6LY Use?
There isn't one answer for every 6LY.
Earlier Yanmar 6LY Engines
Engines such as the 6LY2A-STP use direct injection with an inline mechanical injection pump.
Available components can include:
- Fuel Injectors
- Injector Nozzles
- Inline Injection Pumps
- Fuel Supply Pumps
- Fuel Filters
- Fuel Pipes
- Injector Seals
- Fuel-System Gaskets
Current Yanmar 6LY-CR Engines
The 6LY400 and 6LY440 use a Denso common-rail fuel-injection system.
Available components can include:
- Common-Rail Injectors
- High-Pressure Fuel Pumps
- Common-Rail Components
- Fuel Pressure Sensors
- Fuel Supply Pumps
- High-Pressure Fuel Pipes
- Fuel Filters
- Injector Seals
- Electronic Fuel-Control Components
Yanmar 6LY Fuel Injector Parts
Injector selection depends heavily on the engine generation.
Available components can include:
- Complete Fuel Injectors
- Remanufactured Injectors
- Injector Nozzles for applicable engines
- Injector Seals
- Injector Washers
- Injector O-Rings
- Injector Hardware
- Fuel Pipes
- Common-Rail Components for applicable engines
Injector condition can affect:
- Starting
- Idle quality
- Acceleration
- Engine power
- Fuel consumption
- Cylinder balance
- Exhaust smoke
- Combustion quality
Is the Yanmar 6LY Turbocharged?
Yes. The major 6LY versions covered here use turbocharging and intercooling.
Available turbocharger components can include:
- Complete Turbochargers
- Remanufactured Turbochargers
- Turbocharger Cartridges
- Compressor Components
- Turbine Components
- Bearings
- Seals
- Oil Supply Components
- Oil Drain Components
- Turbocharger Gaskets
- Mounting Hardware
The correct turbocharger must be identified for the specific 6LY model.
Yanmar 6LY Intercooler Parts
The intercooler reduces the temperature of compressed intake air after it leaves the turbocharger.
Available components can include:
- Complete Intercoolers
- Charge-Air Cooler Cores
- Cooler Housings
- End Covers
- Air Connections
- Hoses
- Clamps
- Gaskets
- O-Rings
- Seals
Yanmar 6LY Cylinder Head Parts
Available components can include:
- Complete Cylinder Heads
- Intake Valves
- Exhaust Valves
- Valve Guides
- Valve Seats
- Valve Springs
- Rocker Components
- Injector Components
- Cylinder Head Gaskets
- Cylinder Head Seals
- Associated Hardware
Yanmar 6LY Piston and Internal Engine Parts
Available internal components can include:
- Pistons
- Piston Rings
- Piston Pins
- Connecting Rods
- Connecting Rod Bearings
- Main Bearings
- Thrust Bearings
- Crankshaft Components
- Camshaft Components
- Timing Components
- Associated Gaskets and Seals
Internal component specifications should always be verified against the particular engine model.
Yanmar 6LY Crankshaft and Bearing Parts
Available components can include:
- Complete Crankshafts
- Main Bearings
- Connecting Rod Bearings
- Thrust Bearings
- Connecting Rod Components
- Crankshaft Gear Components
- Front Crankshaft Seals
- Rear Crankshaft Seals
- Vibration Damper Components
Yanmar 6LY Cooling System Parts
The marine cooling system is another important area for maintenance and repair.
Available components can include:
- Freshwater Pumps
- Seawater Pumps
- Raw-Water Pump Components
- Impellers
- Thermostats
- Thermostat Housings
- Heat Exchangers
- Cooling Pipes
- Cooling Hoses
- Temperature Sensors
- Gaskets
- O-Rings
- Seals
Yanmar 6LY Seawater Pump Parts
Available seawater-pump components can include:
- Complete Seawater Pumps
- Raw-Water Pumps
- Impellers
- Pump Shafts
- Bearings
- Mechanical Seals
- Pump Covers
- Wear Components
- Gaskets
- O-Rings
The exact pump specification can differ between 6LY generations and marine installations.
Yanmar 6LY Heat Exchanger Parts
Available components can include:
- Complete Heat Exchangers
- Heat Exchanger Cores
- End Covers
- End Caps
- Gaskets
- O-Rings
- Seals
- Raw-Water Connections
- Coolant Connections
- Associated Hardware
Yanmar 6LY Lubrication System Parts
Available lubrication components can include:
- Engine Oil Pumps
- Oil Filters
- Oil Filter Elements
- Oil Filter Housings
- Oil Coolers
- Oil Pressure Components
- Oil Lines
- Oil Pan Components
- Oil Seals
- Lubrication-System Gaskets
Yanmar 6LY Electronic Components
Electronic parts are especially relevant to later-generation engines.
For example, the current 6LY-CR range is electronically controlled through Yanmar's VC20 Vessel Control System, while earlier 6LY2A engines use mechanical controls.
Depending on engine generation, components can include:
- Engine Control Components
- Fuel Pressure Sensors
- Oil Pressure Sensors
- Coolant Temperature Sensors
- Engine Speed Sensors
- Position Sensors
- Wiring Harnesses
- CAN-Bus Components
- Vessel-Control Components
- Monitoring Components
- Electrical Connections
Yanmar 6LY Gaskets and Seals
Available sealing components can include:
- Cylinder Head Gaskets
- Valve Cover Gaskets
- Intake Gaskets
- Exhaust Gaskets
- Turbocharger Gaskets
- Intercooler Gaskets
- Heat Exchanger Gaskets
- Water Pump Gaskets
- Oil-System Gaskets
- Injector Seals
- Crankshaft Seals
- O-Rings
- Complete Gasket Sets
- Engine Seal Kits
Yanmar 6LY Overhaul Parts
Depending on the exact engine generation and overhaul scope, available components can include:
- Pistons
- Piston Rings
- Piston Pins
- Main Bearings
- Connecting Rod Bearings
- Thrust Bearings
- Connecting Rod Components
- Cylinder Head Components
- Intake and Exhaust Valves
- Fuel Injectors
- Crankshaft Seals
- Gasket Sets
- Seal Kits
- Freshwater Pumps
- Seawater Pumps
- Oil Pumps
- Turbocharger Components
- Cooling-System Components
Major replacement components can also include:
- Crankshafts
- Camshafts
- Connecting Rods
- Complete Cylinder Heads
- Turbochargers
- Intercoolers
- Heat Exchangers
- Fuel-Injection Components
What Applications Use the Yanmar 6LY?
The 6LY family has been used across a broad range of marine applications. Yanmar specifically positions the current 6LY-CR for cruising, performance/racing, repowering, new builds, and light-commercial applications, with both shaft and jet-drive solutions.
Applications can include:
- Motor Yachts
- Sport-Fishing Boats
- Cruising Boats
- Fast Powerboats
- Planing-Hull Vessels
- Light Commercial Vessels
- Fast Workboats
- Patrol and Service Craft
- Passenger Craft
- Repower Projects
Which Yanmar 6LY Do I Have?
Before requesting parts, check the complete model designation on the engine identification plate.
For example:
6LYA-STP
6LY2A-STP
6LY3-STP
6LY400
6LY440
For accurate parts identification, provide:
- Complete engine model
- Engine serial number
- Existing part number
- Component description
- Quantity required
- Marine gear information where relevant
- Fuel-system type if known
- Clear photographs of the component
- Delivery country or port
This is particularly important with injectors, injection pumps, common-rail components, turbochargers, electronic controls, seawater pumps, heat exchangers, starter motors, alternators, and other generation-specific components.