Perkins 4.108 Marine Engine Spare Parts
The Perkins 4.108 Marine Engine is one of the best-known compact Perkins diesel engines used in marine propulsion. Perkins identifies the 4.108 as a four-cylinder engine with approximately 1.8 litres displacement, and the engine family has a long history in marine applications.
The 4.108 can still be found in sailing yachts, motor yachts, fishing boats, classic vessels and older commercial craft. Because many engines have accumulated decades of service, parts requirements can range from routine filters and raw-water pump components to fuel-injection equipment, cylinder heads, pistons, bearings and complete overhaul components.
Alfa Marine Spare Parts supports Perkins 4.108 Marine Engine Spare Parts requirements for:
- Planned Maintenance
- Yacht Maintenance and Refit
- Commercial Vessel Repairs
- Engine-Room Repairs
- Fuel-System Repairs
- Cooling-System Repairs
- Cylinder Head Repairs
- Internal Engine Repairs
- Major Engine Overhauls
- Classic Vessel Restoration
- Spare Parts Planning
Depending on component and availability, supply options can include:
- Genuine Perkins Parts
- OEM-Quality Components
- Selected Aftermarket Parts
- Remanufactured Components
- Maintenance Components
- Repair Parts
- Overhaul Parts
What Are the Technical Specifications of the Perkins 4.108?
The Perkins 4.108 is an established compact four-cylinder diesel engine family. Perkins currently identifies the family as a 1.8-litre, four-cylinder engine and continues to list 4.108-series replacement components in its parts catalog.
SpecificationPerkins 4.108ManufacturerPerkinsEngine Family4.108ApplicationMarine Propulsion / Other Diesel ApplicationsConfigurationInline 4-CylinderCycleFour-Stroke DieselFuelDieselDisplacementApprox. 1.8 Litres / 108 cu inFuel SystemMechanical Diesel InjectionMarine CoolingCommonly Freshwater / Heat-Exchanger ArrangementTypical ApplicationsSailing Yachts, Motor Yachts & Small Marine Craft
Exact marine power ratings, cooling arrangements, fuel equipment and installed accessories can vary by build and vessel installation.
For this reason, the engine serial number should always be used when confirming replacement components. Perkins states that the serial number is the only reliable way to identify the exact engine specification and compatible replacement parts.
What Does Perkins 4.108 Mean?
The designation refers to two basic engine characteristics:
4 — Four cylinders.
108 — Approximately 108 cubic inches of displacement.
That corresponds to approximately 1.8 litres.
Are All Perkins 4.108 Marine Engines the Same?
No.
This is particularly important when sourcing spare parts.
Individual engines can differ according to:
- Production Period
- Engine Build
- Marine Conversion
- Cooling Arrangement
- Fuel Injection Equipment
- Raw-Water Pump
- Exhaust Arrangement
- Electrical Equipment
- Previous Repairs
- Previous Overhauls
Perkins' own parts guidance emphasizes checking the exact engine serial number rather than assuming compatibility from the model family alone.
Why Is the Perkins 4.108 Serial Number Important?
Many 4.108 engines have undergone years of maintenance, repairs and vessel modifications.
Components may have been:
- Rebuilt
- Reconditioned
- Exchanged
- Replaced
- Superseded
- Modified
- Updated
This can be particularly important when identifying:
- Fuel Injectors
- Fuel Injection Equipment
- Raw-Water Pumps
- Freshwater Pumps
- Starter Motors
- Alternators
- Electrical Components
- Cooling Components
Perkins continues to list individual 4.108-series parts, but its catalog repeatedly advises checking the exact engine serial number for compatibility.
Perkins 4.108 Routine Maintenance Parts
Common maintenance requirements can include:
- Engine Oil Filters
- Fuel Filters
- Fuel-Water Separator Elements
- Air Filter Components
- Raw-Water Pump Impellers
- Drive Belts
- Thermostats
- Gaskets
- O-Rings
- Seals
- Cooling-System Components
- Service Kits
Does an Older Perkins 4.108 Need Special Attention?
Older engines often require attention beyond basic oil and filter changes.
Important areas can include:
- Cooling-System Corrosion
- Raw-Water Pump Condition
- Heat Exchanger Condition
- Fuel-System Cleanliness
- Fuel Injection Equipment
- Lubricating-Oil Pressure
- Oil Leakage
- Coolant Leakage
- Exhaust-System Condition
- Electrical Connections
- Hoses
- Seals
- Gaskets
- Engine Mounts
Perkins also emphasizes the importance of proper lubrication and cooling-system maintenance for engine life.
Perkins 4.108 Fuel-System Parts
Potential requirements can include:
- Fuel Injectors
- Injector Nozzles
- Fuel Injection Pump
- Injection Pump Components
- Fuel Lift Pump
- Primary Fuel Filters
- Secondary Fuel Filters
- Fuel-Water Separator Components
- Injector Pipes
- Fuel Supply Pipes
- Fuel Return Components
- Fuel Connections
- Seals
- Gaskets
- O-Rings
Perkins 4.108 Fuel Injectors
Potential requirements can include:
- Complete Fuel Injectors
- Injector Nozzles
- Injector Sealing Components
- Injector Pipes
- Fuel Return Components
- Associated Hardware
What Are Possible Signs of Perkins 4.108 Injector Problems?
Possible symptoms can include:
- Difficult Starting
- Rough Running
- Uneven Cylinder Operation
- Excessive Exhaust Smoke
- Reduced Engine Power
- Increased Fuel Consumption
- Abnormal Combustion Noise
These symptoms do not automatically confirm injector failure.
Fuel quality, fuel delivery, injection-pump condition, compression and air supply should also be investigated.
Perkins 4.108 Fuel Injection Pump Parts
Potential requirements can include:
- Complete Fuel Injection Pump
- Reconditioned Fuel Injection Pump
- Injection Pump Components
- Pump Seals
- Pump Gaskets
- Fuel Connections
- Associated Fuel-System Parts
Why Should the Existing Injection Pump Be Identified?
A 4.108 that has been operating for decades may no longer have its original injection pump.
The pump may previously have been:
- Rebuilt
- Reconditioned
- Exchanged
- Replaced
- Superseded
Useful identification information can include:
- Engine Serial Number
- Pump Manufacturer
- Pump Model
- Pump Identification Number
- Existing Perkins Part Number
- Clear Photographs
Perkins 4.108 Fuel Lift Pump Parts
Potential requirements can include:
- Complete Fuel Lift Pump
- Pump Components
- Pump Gaskets
- Seals
- Fuel Connections
- Associated Fuel Lines
Can a Weak Lift Pump Cause Starting Problems?
Yes.
Insufficient fuel supply can contribute to:
- Extended Cranking
- Difficult Starting
- Unstable Idle
- Reduced Engine Power
- Engine Stalling
Fuel filters, air leaks and injection equipment should also be checked before the lift pump is automatically blamed.
Perkins 4.108 Fuel Filter Parts
Potential requirements can include:
- Primary Fuel Filters
- Secondary Fuel Filters
- Fuel Filter Elements
- Fuel-Water Separators
- Filter Housings
- Filter Seals
- O-Rings
- Drain Components
Why Is Clean Fuel Important on an Older Perkins 4.108?
Older marine fuel tanks can accumulate:
- Water
- Sediment
- Rust
- Tank Debris
- Microbial Contamination
Contaminated fuel can contribute to:
- Injector Wear
- Injection-Pump Wear
- Difficult Starting
- Poor Combustion
- Unstable Engine Operation
- Reduced Power
Perkins 4.108 Air Intake Parts
Potential requirements can include:
- Air Cleaner Components
- Air Filter Components
- Intake Hoses
- Intake Pipes
- Intake Manifold Components
- Clamps
- Gaskets
- Seals
Perkins still lists air-filter components associated with the 4.108 family in its current parts catalog.
Can Restricted Airflow Cause Black Smoke?
Yes.
Restricted airflow can contribute to:
- Black Exhaust Smoke
- Reduced Engine Power
- Poor Acceleration
- Increased Fuel Consumption
- Increased Exhaust Temperature
Fuel-injection condition and engine loading should also be considered during diagnosis.
Perkins 4.108 Raw-Water Cooling System Parts
Marine 4.108 installations commonly use a freshwater-cooled engine circuit with a seawater side for heat removal.
Potential requirements can include:
- Complete Raw-Water Pump
- Seawater Pump
- Flexible Impeller
- Pump Cover
- Pump Shaft
- Bearings
- Mechanical Seals
- Cooling Hoses
- Seawater Pipes
- Connections
- Gaskets
- O-Rings
Why Is the Perkins 4.108 Raw-Water Pump Important?
The raw-water pump maintains seawater circulation through the marine cooling system.
Reduced flow can contribute to:
- Engine Overheating
- Rising Coolant Temperature
- High Exhaust Temperature
- Reduced Heat Exchanger Performance
- Wet-Exhaust Cooling Problems
What Should Be Checked When 4.108 Seawater Flow Drops?
Areas to investigate can include:
- Seacock
- Raw-Water Intake
- Sea Strainer
- Intake Hose
- Raw-Water Pump
- Flexible Impeller
- Pump Cover
- Cooling Hoses
- Heat Exchanger
- Exhaust Cooling Circuit
- Downstream Cooling Passages
Perkins 4.108 Raw-Water Pump Impeller
The flexible impeller is an important routine-service component.
If an impeller has broken blades, fragments can potentially travel into:
- Cooling Hoses
- Pipe Connections
- Heat Exchanger Passages
- Other Cooling Components
Installing a new impeller may not completely restore seawater flow if old pieces remain trapped downstream.
Perkins 4.108 Freshwater Pump Parts
Potential requirements can include:
- Complete Freshwater Pump
- Coolant Circulation Pump
- Pump Housing
- Pump Shaft
- Bearings
- Seals
- Gaskets
- O-Rings
Perkins 4.108 Heat Exchanger Parts
Potential requirements can include:
- Complete Heat Exchanger
- Heat Exchanger Core
- Tube Bundle
- Housing
- End Covers
- End-Cap Seals
- Raw-Water Connections
- Coolant Connections
- Gaskets
- O-Rings
- Seals
What Can Restrict a Perkins 4.108 Heat Exchanger?
Possible causes can include:
- Salt Deposits
- Scale
- Marine Growth
- Sediment
- Corrosion
- Broken Impeller Pieces
- Other Debris
Cooling-system condition is especially important on older marine engines, and Perkins describes the cooling system as essential in preventing overheating and engine breakdown.
Why Can a Perkins 4.108 Overheat Under Load?
At idle, the engine produces less heat.
When propulsion load increases, the cooling system has to remove more heat. A partially restricted cooling system may therefore appear acceptable at idle but become inadequate under load.
Areas to investigate can include:
- Seacock
- Sea Strainer
- Raw-Water Intake
- Raw-Water Pump
- Impeller
- Cooling Hoses
- Heat Exchanger
- Thermostat
- Freshwater Pump
- Coolant Level
- Coolant Condition
- Exhaust Cooling Circuit
Perkins 4.108 Thermostat Parts
Potential requirements can include:
- Thermostats
- Thermostat Housing
- Thermostat Gaskets
- O-Rings
- Seals
- Associated Hardware
Perkins 4.108 Lubrication-System Parts
Potential requirements can include:
- Engine Oil Filters
- Oil Filter Elements
- Oil Pump Components
- Oil Cooler
- Oil Cooler Components
- Oil Pressure Components
- Oil Pipes
- Oil Lines
- Oil Pan Components
- Gaskets
- O-Rings
- Crankshaft Seals
What Can Low Oil Pressure Mean on a Perkins 4.108?
Possible causes can include:
- Incorrect Oil Level
- Incorrect Oil Grade
- Deteriorated Oil
- Restricted Oil Filter
- Oil Pump Wear
- Excessive Bearing Clearance
- Internal Engine Wear
- Oil Pressure Sender Problems
- Instrumentation Problems
Perkins notes that lower-quality oil can increase wear and shorten engine life, so oil quality and condition should also be considered during maintenance.
Perkins 4.108 Oil Cooler Parts
Depending on the installation, potential requirements can include:
- Complete Oil Cooler
- Oil Cooler Core
- Oil Cooler Housing
- Oil Connections
- Cooling Connections
- Gaskets
- O-Rings
- Seals
Perkins 4.108 Cylinder Head Parts
Potential requirements can include:
- Complete Cylinder Head
- Intake Valves
- Exhaust Valves
- Valve Guides
- Valve Seats
- Valve Springs
- Rocker Components
- Valve-Train Components
- Cylinder Head Gasket
- Valve Cover Gaskets
- Injector Sealing Components
When Should a Perkins 4.108 Cylinder Head Be Inspected?
Inspection may become necessary following:
- Severe Overheating
- Head-Gasket Failure
- Coolant Loss
- Low Compression
- Valve Damage
- Coolant Leakage
- Abnormal Combustion
- Major Engine Overhaul
Should an Older Perkins 4.108 Cylinder Head Automatically Be Replaced?
No.
The decision should be based on inspection and measurements.
Important areas include:
- Cracking
- Corrosion
- Flatness
- Valve Condition
- Valve-Seat Condition
- Valve-Guide Wear
- Sealing Surfaces
- Previous Machining
- Overheating Damage
A serviceable cylinder head may still be suitable for rebuilding.
Perkins 4.108 Pistons and Piston Rings
Potential requirements can include:
- Pistons
- Piston Ring Sets
- Piston Pins
- Piston Pin Bushings
- Retaining Components
What Can Worn Perkins 4.108 Piston Rings Cause?
Possible symptoms include:
- Excessive Blow-By
- Increased Oil Consumption
- Reduced Compression
- Difficult Starting
- Exhaust Smoke
- Reduced Engine Power
Piston, ring and cylinder condition should be evaluated together.
Perkins 4.108 Connecting Rod Parts
Potential requirements can include:
- Connecting Rods
- Connecting Rod Bearings
- Small-End Bushings
- Connecting Rod Bolts
- Associated Hardware
Perkins 4.108 Main and Connecting Rod Bearings
Potential requirements can include:
- Main Bearing Sets
- Connecting Rod Bearing Sets
- Big-End Bearings
- Thrust Bearings
- Thrust Washers
Why Should Bearing Size Be Checked Carefully?
An older engine may have undergone previous crankshaft machining.
The crankshaft may have been:
- Polished
- Reground
- Repaired
- Replaced
Bearings should therefore be selected based on the crankshaft's actual dimensions rather than engine model alone.
Perkins 4.108 Crankshaft Parts
Potential requirements can include:
- Complete Crankshaft
- Main Bearings
- Connecting Rod Bearings
- Thrust Components
- Crankshaft Gear Components
- Front Crankshaft Seal
- Rear Crankshaft Seal
What Should Be Checked on a Perkins 4.108 Crankshaft During Overhaul?
Inspection can include:
- Main Journal Diameter
- Connecting Rod Journal Diameter
- Journal Surface Condition
- Scoring
- Taper
- Out-of-Round Condition
- Heat Damage
- Previous Grinding
- General Crankshaft Condition
Perkins 4.108 Camshaft and Timing Parts
Potential requirements can include:
- Camshaft
- Camshaft Bearings
- Timing Gears
- Gear-Train Components
- Timing Covers
- Timing Cover Gaskets
- Valve-Train Components
Perkins 4.108 Gaskets and Seals
Potential requirements can include:
- Cylinder Head Gasket
- Valve Cover Gaskets
- Intake Gaskets
- Exhaust Gaskets
- Raw-Water Pump Gaskets
- Freshwater Pump Gaskets
- Heat Exchanger Gaskets
- Oil Cooler Gaskets
- Injector Seals
- Front Crankshaft Seal
- Rear Crankshaft Seal
- O-Rings
- Upper Gasket Sets
- Lower Gasket Sets
- Complete Engine Gasket Sets
- Engine Seal Kits
Are All Perkins 4.108 Gasket Sets the Same?
No.
The 4.108 family covers engines from different production periods and installations.
A gasket set should be matched using the exact engine serial number and build information.
Perkins 4.108 Starter Motor Parts
Potential requirements can include:
- Complete Starter Motor
- Starter Solenoid
- Relays
- Electrical Connections
- Associated Hardware
Perkins currently lists starter-motor components specifically associated with the 4.108 Series, while advising users to verify the exact engine serial number.
Does Slow Cranking Always Mean Starter Failure?
No.
Possible causes can include:
- Weak Batteries
- Corroded Battery Terminals
- Damaged Battery Cables
- Poor Ground Connections
- Excessive Electrical Resistance
- Relay Problems
- Control-Wiring Problems
Marine corrosion can create substantial electrical resistance in older installations.
Perkins 4.108 Alternator Parts
Potential requirements can include:
- Complete Alternator
- Alternator Components
- Drive Belts
- Pulleys
- Belt-Tensioning Components
- Electrical Connections
On older vessels, the currently installed alternator should be identified because charging-system components may have been changed during previous refits.
Perkins 4.108 Exhaust-System Parts
Depending on the marine installation, potential requirements can include:
- Exhaust Manifold Components
- Exhaust Elbows
- Mixing Elbows
- Exhaust Connections
- Exhaust Gaskets
- Seals
- Clamps
- Associated Hardware
Why Should an Older 4.108 Exhaust Elbow Be Inspected?
In a wet-exhaust installation, hot exhaust gases and seawater operate close together.
Internal corrosion and deposits can contribute to:
- Restricted Exhaust Flow
- Reduced Engine Power
- Increased Exhaust Temperature
- Increased Exhaust Smoke
- Poor Engine Response
The internal condition may be considerably worse than the outside appearance suggests.
Perkins 4.108 Engine Overhaul Parts
Depending on inspection findings, overhaul requirements can include:
- Pistons
- Piston Rings
- Piston Pins
- Main Bearings
- Connecting Rod Bearings
- Connecting Rods
- Small-End Bushings
- Thrust Components
- Cylinder Head Components
- Intake Valves
- Exhaust Valves
- Crankshaft Seals
- Complete Gasket Sets
- Seal Kits
- Fuel-System Components
- Cooling-System Components
- Lubrication-System Components
More extensive repairs may require:
- Complete Cylinder Head
- Crankshaft
- Camshaft Components
- Fuel Injectors
- Fuel Injection Pump
- Raw-Water Pump
- Freshwater Pump
- Heat Exchanger
- Oil Cooler
- Starter Motor
- Alternator
Is There One Standard Perkins 4.108 Overhaul Kit?
Not necessarily.
The correct overhaul package depends on:
- Exact Engine Version
- Engine Serial Number
- Engine Build Information
- Operating Hours
- Maintenance History
- Previous Overhauls
- Cylinder Measurements
- Piston Condition
- Crankshaft Dimensions
- Bearing Sizes
- Cylinder Head Condition
- Fuel-System Condition
- Cooling-System Condition
Why Should Inspection Come Before Ordering a 4.108 Overhaul Kit?
Many 4.108 engines have undergone previous internal repairs.
For example, if the crankshaft was reground during an earlier overhaul, standard-size bearings may no longer be correct.
A better process is:
Identify the engine → inspect the components → measure where necessary → order the correct parts.
What Information Should I Provide for Perkins 4.108 Parts?
For accurate Perkins 4.108 Marine Engine Spare Parts identification, provide:
- Exact Perkins 4.108 Version
- Engine Serial Number
- Engine Build Information
- Existing Perkins Part Number, if available
- Component Manufacturer Number
- Fuel Injection Pump Identification Where Relevant
- Raw-Water Pump Identification Where Relevant
- Part Description
- Quantity Required
- Clear Photographs
- Vessel Application
- Marine Gear Information Where Relevant
- Delivery Country or Nearest Port
Perkins specifically states that the engine serial number should be used to confirm the exact engine specification and compatible replacement parts.
For older 4.108 marine installations, photographs of the engine identification plate and actual component being replaced can be especially valuable.