Engine MaintenanceEngine Maintenance

Chapter 5Chapter 5

Inboard Diesel Engines Part 2Inboard Diesel Engines Part 2

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Objectives for the StudentObjectives for the Student

1.Have knowledge of routine maintenance procedures for diesel engines

2.Have an understanding of troubleshooting techniques for fuel, cooling, and lubrication systems

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The Diesel EngineThe Diesel Engine

Compression Compression IgnitionIgnition Air is heated Air is heated

by by compressioncompression

fuel is injected fuel is injected and and autoignitesautoignites

No spark plugNo spark plug

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Routine Maintenance - Routine Maintenance - FuelFuel

Fuel systemFuel system Primary filterPrimary filter Secondary filterSecondary filter Bleeding the systemBleeding the system

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Fuel System IssuesFuel System Issues

Cleanliness is critical to Cleanliness is critical to smooth operationsmooth operation

Tanks are ventedTanks are vented Water gets in, even through Water gets in, even through

condensationcondensation Bacteria growBacteria grow Water and sludge get pulled Water and sludge get pulled

into the fuel systeminto the fuel system

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Fuel System MaintenanceFuel System Maintenance

A dual filter system is commonly A dual filter system is commonly usedused Primary filterPrimary filter Low pressure pumpLow pressure pump Secondary filterSecondary filter High pressure pumpHigh pressure pump InjectorInjector

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Fuel System MaintenanceFuel System Maintenance

Primary filter – Primary filter – 30 micron30 micron Contains a water Contains a water

separatorseparator Secondary filter Secondary filter

– 1 micron– 1 micron

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Cutaway of a Fuel FilterCutaway of a Fuel Filter

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Bleeding the SystemBleeding the System

After servicing, the air After servicing, the air must be removed from the must be removed from the systemsystem Air lock can prevent startingAir lock can prevent starting Fuel is needed to lubricate Fuel is needed to lubricate

pump and injectorspump and injectors

1010

Bleeding the SystemBleeding the System

Bleed in stagesBleed in stages1.1. Use low pressure Use low pressure

feed pump to feed pump to clear the filtersclear the filters

2.2. Crank the engine Crank the engine to bleed each to bleed each injector lineinjector line

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Routine Maintenance - Routine Maintenance - CoolingCooling

Fundamentally the same as Fundamentally the same as gasoline enginesgasoline engines

May be direct or indirectMay be direct or indirect Raw water impeller is the usual Raw water impeller is the usual

suspectsuspect

1212

Routine Maintenance - Routine Maintenance - LubeLube

Fundamentally the same as Fundamentally the same as gasoline enginesgasoline engines

Use “C” grade oil for diesel Use “C” grade oil for diesel serviceservice

1313

Routine Maintenance - Routine Maintenance - LubeLube

Basic reminders:Basic reminders: Check the oil Check the oil dailydaily Change oil and filter regularlyChange oil and filter regularly Monitor oil pressureMonitor oil pressure

Diesels run under high bearing loadsDiesels run under high bearing loads 40 to 60 psi at all times40 to 60 psi at all times 275 to 400 kPa at all times275 to 400 kPa at all times

1414

Check the ObviousCheck the Obvious Check the EasyCheck the Easy Check SystematicallyCheck Systematically Make No Erratic AdjustmentsMake No Erratic Adjustments

TroubleshootingTroubleshooting

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The fuel system is the most The fuel system is the most likely cause of failure to startlikely cause of failure to start

Fuel in tank?Fuel in tank? Check for fuelCheck for fuel Check for contaminationCheck for contamination

Engine shut off secured?Engine shut off secured? Is the weather very cold?Is the weather very cold?

Fuel gelationFuel gelation

Troubleshooting – FuelTroubleshooting – Fuel

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Indications Indications Engine stops, temperature gauge reads hotEngine stops, temperature gauge reads hot

Check the drive belt on the water pump firstCheck the drive belt on the water pump first Is it stretched or broken?Is it stretched or broken? A temporary belt can be made from a Nylon beltA temporary belt can be made from a Nylon belt

A too hot engine will usually restart after it A too hot engine will usually restart after it has cooledhas cooled After restarting check for water exiting from the After restarting check for water exiting from the

exhaustexhaust No water exiting, check the water pump for leaking No water exiting, check the water pump for leaking

water or broken impellerwater or broken impeller If water Is exiting from the exhaust, the prime If water Is exiting from the exhaust, the prime

suspect Is the thermostatsuspect Is the thermostat

Troubleshooting – CoolingTroubleshooting – Cooling

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Lack of oilLack of oil OverheatingOverheating Worn bearingsWorn bearings Fuel dilution of oilFuel dilution of oil Oil pump wearOil pump wear Oil pressure gauge Oil pressure gauge

malfunctionmalfunction

Troubleshooting – LubricationTroubleshooting – Lubrication

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Troubleshooting – Glow PlugTroubleshooting – Glow Plug

Check for fuel gelationCheck for fuel gelation Check fuses on engineCheck fuses on engine If you decide to change the If you decide to change the

glow plugs:glow plugs: Keep the seat cleanKeep the seat clean Tighten carefully to Tighten carefully to

specificationspecification

1919

Remember…Remember…

You should be able to You should be able to identify problems and identify problems and explain them to a mechanicexplain them to a mechanic