Main engine Troubleshooting part 2

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 ENGINE DOES NOT FIRE

CAUSES:

  • Less fuel being injected or the speed setting knob is set too low.
  • Governor does not release the regulating linkage.
  • VIT & FQS functions are too late.
  • Start air pressure is insufficient to turn engine fast enough.
  • Fuel is unsuitable or its viscosity high.
  • Compression pressure is too low due to faulty piston ring sealing or the exhaust valve closing.
  • Fuel pump defect.
  • Injector nozzle needle sticking or holes blocked.
  • Suction or spill valves leaking or struck.
  • Pump push rods jammed or the fuel cams displaced or incorrect timings.
  • Fuel pump relief valve leaking.

BROKEN PISTON RING

CAUSES:

  • Excessive thermal load, insufficient cooling, or a distorted piston crown.
  • Excessive piston ring clearance or distorted grooves.
  • Sticking of piston rings or incompatible materials.
  • Excessive lubrication or loss of lubrication.
  • Collapse of piston rings.

EFFECTS:

  • Loss of compression.
  • Blow past of combustion gases.
  • Scavenge fire.
  • Scuffing of the cylinder liner.

REMEDIAL ACTION:

Identify cause and take corrective action.

BEARING TEMPERATURE INCREASE

CAUSES:

  • Low lube oil pressure supply to bearing or low oil level in supply tank.
  • Air lock in the lube oil or the lubricating grooves obstructed.
  • Oil piping defective or lube oil valves shut.
  • Lube oil contains water or metal impurities.
  • Excessive bearing clearances, excessive wear or important tightening.

LUBE OIL SUMP LEVEL RISING

CAUSES:

  • Pitching, rolling or changes in cargo loading.
  • Water leakage from piston cooling or jacket water system.
  • Lube oil purifier wrongly set.
  • Transfer pump valves wrongly lined up.
  • Lube oil inlet line valve of the storage tank may be open.

REMEDIAL ACTION:

Identify cause and take corrective action.

AUTOMATIC STOPPING OF THE ENGINE

CAUSES:

  • Activation of safety shut down or over speed cut-out device.
  • Control air pressure in the shut-down servomotor too low, causing pressure to pull the fuel linkage back to zero.
  • Governor defective.
  • Fuel supply stopped due to the clogged filter or empty tank or air lock.

REMEDIAL ACTION:

Identify cause and take corrective action.

REDUCED COMPRESSION PRESSURE

CAUSES:

  • This is due to worn piston rings.
  • Worn liner.
  • Worn piston crown.
  • Worn exhaust valve.
  • Incorrect exhaust valve timings
  • Identify cause and take corrective action.

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