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YANMAR Marine Engine Trouble Shooting

YANMAR Trouble Shooting: Possible Cause, Possible Remedy

 

No response from starter motor

No battery voltage to starter -  Verify wiring and battery connection (power and ground)

Battery discharged - Charge or replace battery, verify alternator charging

Tripped overcurrent protection - Correct fault, replace or reset overcurrent protection

No signal from control system - No power to control system

Defective starter solenoid - Replace starter solenoid

Defective starter motor - Replace starter motor

 

Engine will crank but not start

Engine not getting fuel - Check fuel level, filter, fuel pump, verify no air in fuel lines

ECU is not functioning - See Engine Troubleshooting

Tripped overcurrent protection - Correct fault, replace or reset overcurrent protection

No preheat (cold condition) - See Preheat Troubleshooting

 

Engine runs and shuts down

ECU shutdown - Use display to view ECU diagnostic codes, use ECU diagnostic tool for more detailed information

Circuit overload protection tripped - Correct overload, keep control system from overheating (over 167° F or 75° C)

Voltage transients (spikes) - Add suppressor diodes, protect from nearby lightening strikes, shield induced spikes from other equipment, add electric motor control relay

Defective control system - See Control System Troubleshooting

Alternator not charging battery

Broken or slipping alternator drive belt - Adjust or replace alternator drive belt

Alternator not excited - Verify excitation circuit connected, replace faulty regulator

Alternator output not connected - Install charge wire

Alternator not grounded - Clean or add ground connection

Alternator faulty - Replace faulty alternator

 

ECU does not power-up

No power to ECU - Locate reason for lack of power and correct (Circuit overloaded? Failed suppressor diode? Faulty wiring?)

Tripped overcurrent protection - Correct fault, replace or reset overcurrent protection

Faulty ECU - Replace ECU

Optional e-stop engaged - Disengage e-stop

 

Engine not getting fuel

Empty fuel tank - Fuel engine

Clogged filter - Replace filter

Air in fuel lines - Bleed fuel lines

Low fuel pressure - Replace faulty fuel pump and/or clogged filter

Faulty fuel pump - Replace fuel pump, correct wiring fault (electric fuel pump)


Engine is hard to start in cold conditions

Start attempt before preheat complete - Wait for preheat time to elapse, crank as soon as time elapses

Heater faulty - Replace heater

Heater relay faulty - Replace relay

Preheat control not functioning - Correct wiring, correct ECU configuration

Faulty control system - Repair or replace ECU

 

Engine produces excessive white smoke after starting

Afterglow not enabled - Reconfigure ECU

Heater faulty - Replace heater

Heater relay faulty - Replace relay

Preheat control not functioning - Correct wiring, correct ECU configuration

Faulty control system - Repair or replace ECU

 

Control system does not perform self test

Tripped overcurrent protection - Correct fault, replace or reset overcurrent protection

Faulty connection to battery - Correct battery connections

Faulty control system - Repair or replace control system

 

Control system performs normal self test, engine cranks, runs and shuts down

Engine Stop LED illuminated - Correct ECU stop condition, use ECU diagnostics

 

Display does not display data

Display lost power - Turn on key, verify display plugged into harness

Engine Source address incorrect - Change Engine Address in Configuration

Display Address incorrect - Change Display Address to 40 (default)

Display configuration problem - Reset display using Restore Defaults

CANbus failure - Check CANbus

ECU not sending data - Repair or replace ECU