Marine Electrical
Courses Online Engine Electrics
Marine Electrical Courses Online Engine Electrics covers several important subsystems that enable a diesel engine to start, operate and be monitored. The following is the Chapter Contents list from The Marine Electrical and Electronics Bible 4th Edition. You can buy a copy here.
15. Engine Electrical and Instrumentation; Diesel Engine Starting Systems. Diesel Engine Controls. Electric Engine Starters. Starter Types. Starter Installation, Maintenance and Troubleshooting. Preheating Systems. Preheater Maintenance. Preheater Glow Plug Troubleshooting. Engine Starting Recommendations. Engine Starting Systems. Starting System Configurations. Starting System Failure Mode Analysis. Starting System Diagrams. Engine Instrumentation. Pressure Monitoring. Temperature Monitoring. Exhaust Gas Temperature Monitoring. Engine Tachometers. Engine Alternator Tachometers. Electrical System Monitoring. Hour Counters and Clocks. Acoustic Alarm Systems. Instrumentation Maintenance. Gauge Testing. Engine Alarm Set Points. Sensor Testing. Crankcase Oil Mist Detection. Engine Space Oil Mist Detectors. Fuel Monitoring. Solenoid Valves. Programmable Logic Controllers. PLC Programming. PLC Installation. PLC Troubleshooting. Control Circuit Devices. Engine Instrument Troubleshooting. Engine and Transmission Control Systems.
Marine Electrical
Courses Online Engine Electrics
Things that are within a boat owner’s ability to control are the wiring installation. The connection of the negative cable which should be attached as close as practicable to the starter motor. In most cases it is fastened at the closest engine point, which generally makes a poor contact and inserts resistance into the circuit, as the marine diesel engine block becomes part of the circuit. Starter motor design is generally robust as it must withstand the shocks of meshing, engine vibration, salt and moisture laden air, water, oil, temperature extremes, and high levels of overload. Marine Electrical Courses Online Engine Electrics has answers to questions.
Marine Electrical
Courses Engine Electrics
Marine diesel engine starter motors are by default located low down towards engine bilges, subject to leakages from seawater cooling systems, seawater injection points into exhaust elbows, as well as the unexpected high bilge level. The position is normally out of sight, hard to access and therefore general inspections are often cursory and inadequate. Another area to check is whether you can physically remove the starter as in many installations this is extraordinarily difficult, with tool access to remove holding bolts nearly impossible. One thing an engine manufacturer never really considers is access to starters and that is all up to the boat installer. A little removal practice can pay dividends when things go wrong. Remove each bolt and apply some thread lubricant so that bolts don’t seize in. If oil and coolant or seawater is leaking at the top end then it's probably leaking over the starter also. Corrosion can be rapid on a starter with partial seizure a common issue so starting the engine every week or two will assist in keeping things moving.
Engine Electrics and Control Systems.
Preventive maintenance is essential to ensuring reliability of the engine starter motor. A common problem especially on little used vessels is the formation of surface corrosion, or accumulations of dirt on the shaft and pinion gear assembly, and lack of operation and lubrication causes seizure or a failure to engage. It is good practice to operate the starter as often as possible, the heat dries the windings out. Remove the starter every 12-18 months or prior to an extended cruise to clean and lightly oil the components according to manufacturer’s recommendations. Alternatively drop the starter into your local automotive electrician who can run a quick test and perform the basic maintenance. I carry a complete starter motor as a spare, and given it is the single item most likely to stop engine starting it is cheap insurance. More on starter motors and circuits is here.
Engine Electrics
and Control Systems.
The most common problems occur with seized brushes, and this is due primarily to a lack of use. Where the starter design allows access, manually check that brushes are moving freely in the brush-holders, and that the commutator is also clean. Remove all dust and particles using a vacuum cleaner. If the commutator is dirty, wash it and the brush gear out with a quality spray electrical cleaner if really dirty. Under no circumstances clean and polish the commutator with any abrasive materials as this will quickly ruin it. Commutators build up a surface patina that should not be removed, as sparking brushes will rapidly degrade the surface and edges of the slots.
Engine Electrics
and Control Systems.
There are few of us who haven't heard the deafening silence of that ominous click, and a failure to start, or a chattering solenoid or a failure to get the engine turning over fast enough to start. The following are typical faults to look at when troubleshooting.
LOW VOLTAGE
Low voltage is the most common cause of hard starts, and the battery and battery connections are the first place to look. The main starter motor and solenoid terminals are the next common failure area and often work loose or make inadequate contact. Warm or hot terminals are a good sign of problems and I have seen smoke curling up on some occasions from battery and starter connections. Also check the engine negative connection, as loose bolts or nuts are common.
OVERHEATING
Winding overheating on diesel engine starter motor is a direct result of attempting too many starts or excessively long start attempts. The marine engine cannot be turned over at the required speed either due to lower voltages, or excessive loads especially in cold conditions where high oil viscosity is a factor. Partial or complete failure of the preheating glow plugs is also a reason for slow starts and this should be looked at.
Engine Electrics and Control Systems.
NOISE and VIBRATION
Excessive starter motor noise and vibration may indicate that bolts are loose. Bearing failures are comparatively few in marine diesel engine boat starters as the number of starts is relatively few. Another cause of noise can be attributable to the pinion drive and the overrunning clutch having defects or jamming when disengaging.
STARTER MOTOR SUMMARY
Without the starter motor the marine diesel engine is just another piece of cold iron. Starter reliability and performance comes down to ensuring the cables and power supply are sound, and the connections secure. In addition, the minimization of seawater exposure and maximization of starts will reduce increase reliability and reduce failures. All these tasks are within the scope of any boat owner, and only require simple vigilance and routine visual tasks. Make starter motor inspection an essential part of your marine engine maintenance regime, it will pay you dividends in safety and reliability. Marine Electrical Courses Online Engine Electrics.