Engine Room Machinery and Systems
What the exam tests
This domain tests your knowledge of the systems that keep a diesel engine running: fuel, lubrication, cooling, combustion air and exhaust, starting, electrical supply and bilge transfer. You should know the flow path, the purpose of each filter, pump and heat exchanger, and the symptoms of common failures.
Core systems
- Fuel: tank to day tank, coarse filter, lift pump, fine filter, injection pump, injectors and return line. Air in the suction side causes hard starting, hunting or a sudden stop.
- Lubrication: sump, pump, filter, cooler and bearings. Low pressure or high temperature requires stopping the engine and finding the cause.
- Cooling: sea water passes through strainer, pump, heat exchanger and overboard. Fresh water passes through the engine and heat exchanger. A raw-water loss shows as rising fresh-water temperature and weak overboard flow.
- Starting: air start needs sufficient receiver pressure and regular draining; battery start needs charged batteries and clean terminals.
- Bilge: bilge pump, high-level alarm and oily-water separator where fitted. Never bypass pollution-control equipment.
Worked example
After a fuel filter change, the engine starts, runs briefly and dies; the primer feels soft. Reasoning: air has entered the fuel suction side. Bleed the low-pressure side at the filter and injection pump, then bleed the high-pressure lines using the maker's procedure. Avoid prolonged cranking, which can flood the exhaust or damage the starter. Restart, check for leaks, log the work and confirm fuel pressure.
Traps
- Fitting a filter with the wrong micron rating or leaving an old gasket in place.
- Using the wrong coolant or mixing incompatible lubricating oils.
- Opening a sea-water strainer while the engine is running, causing flooding or air ingress.
- Overlooking an internal leak in a charge-air or oil cooler.
- Running the bilge pump overboard without checking for oil.