There are various types of difficulties that you might face as an engineer while starting an engine. Here we have given some of then. Below we have given some of the problems that you might face at sea or even at land also with the engines. Let’s have a look at the one by one.
Engine does not start on air, with regulating handle in start position
1) Cause: Air Bottle pressure too low
Remedy : Check operation of air compressors and start them to fill up air bottle.
2) Cause : Air starting valves shut
Remedy : Check air starting valve on air bottle and main air starting valve. Open them if not in working position.
3) Cause : Main air starting valve does not operate
Remedy : Bring main air starting valve in working position using manual lever or tools provided if stuck. If valve is not stuck check for pilot air line supply. This may involve checking electric supply to concerned solenoid valve.
4) Cause : Control air pressure low
Remedy : Check discharge pressure of pressure reducing valve. If low change over to stand by pressure regulating valve. Investigate cause of low working pressure of previous valve in operation. It can be clogged air filter, ruptured diaphragm. Rectify it.
5) Cause: Starting air interlock activated
Remedy : Check for the cause of interlock activation. Check if turning gear is engaged, and disengage it if so. Check if running direction interlock is activated. Confirm that engine turning direction and camshaft position are identical.
6) Cause : Air supply to or from air distributor blocked
Remedy : If there is any valve in air supply line then confirm it is open. If open and no air is coming to the respective cylinder air starting valve then check for sticky air distributor valve. If time is short try starting engine in another rotational position by engaging turning gear and rotating engine to another rotational position so that another distributor valve for another cylinder air starting valve comes into operation.
Engine turns too slowly or irregularly on starting air
1) Cause : Some pistons of air distributor are sticking.
Remedy : Overhaul starting air distributor to free the sticky pistons.
2) Cause : Some cylinder air valves are not operating.
Remedy : Test valves for their operation
and overhaul defective ones.
Remedy : Test valves for their operation
and overhaul defective ones.
Engine turns on starting air but does not pick up on fuel
1) Cause : Sluggish movement of fuel control shaft and associated linkages
Remedy : Lubricate and free the fuel control shaft and associated linkages.
2) Cause : Piston in stop piston is jammed. Remedy : If piston is jammed free it.
3) Cause : Stop piston is activated
Remedy : Check pressures & temperatures activating stop piston such as low lube oil pressure, high cooling water temperature. Restore these parameters to normalcy if abnormal. If this is normal then check for malfunction of pneumatic valve supplying air to stop piston.
4) Cause: Control air pressure to governor is low
Remedy : Check air pressure and change over air reducing valve if it is faulty.
5) Cause : Air lock in the fuel injection lines, pumps & valves.
Remedy : Purge out air from fuel system thoroughly.
6) Cause : Pressure before fuel injection pump is low
Remedy : Check fuel booster pump discharge pressure and bring it to normal.
7) Cause : Fuel injection pump is faulty. In case of Bosch pump plungers may be sticking. In case of valve controlled fuel pumps suction valves may be defective.
Remedy : Identify the fault and rectify it.
8) Cause : Failure of governor amplifier.
Remedy : Rectify governor amplifier.
9) Cause : Fuel pumps are worn out.
Remedy : Replace fuel pumps.
Fuel is injected but does not ignite
1) Cause : Presence of water in fuel
Remedy : Drain off water from fuel tanks, prime fuel valves and fuel pumps. Check for source of ingress of water and rectify.
2) Cause : Fuel valves defective
Remedy : Change fuel valves. Check and overhaul removed fuel injectors.
Remedy : Change fuel valves. Check and overhaul removed fuel injectors.
3) Cause : Compression too low (below 22kg/cm2)
Remedy : Inspect piston rings through ports in liner. Check for leaky exhaust valves.
4) Cause : Fuel injection too late
Remedy : Check fuel pump timing and adjust if required.
5) Cause : Viscosity of fuel too high
Remedy : Raise fuel oil temperature to attain required viscosity.
Remedy : Raise fuel oil temperature to attain required viscosity.
Initial ignition is violent and safety valves lift
1) Cause : Accumulation of oil on piston crown
Remedy : Blow through cylinder with indicator valves open to locate leaky fuel valve. Remove defective fuel valve and replace with spare overhauled one.
Initial ignition is violent and cylinder safety valves lift
1) Cause : Accumulation of oil on piston crown
Remedy : Blow through cylinder with indicator valves open to locate leaky fuel valve. Remove defective fuel valve and replace with spare overhauled one.
2) Cause : Sluggish movement of fuel control shaft or individual fuel pump rack making fuel pump injection high (for respective fuel lever position.)
Remedy : Lubricate bearings of fuel control shaft and free its movement. Lubricate individual fuel pump rack and make their movement free.
3) Cause : Scavenging air pressure is low
Remedy : Check auxiliary blower is running. Check air and gas passages and clean if required.
(Note – If fuel oil is present on piston crown due to first injection not igniting then due to scavenge air pressure low this fuel does not get expelled and accumulates on crown causing violent ignition before TDC)
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