Maintenance Procedures. Test 3 – Online Maritime Tests

When maintenance work is to be carried out on an electric motor mounted on a centrifugal water pump with automatic start, should you;

Isolate the suction and delivery valves then commence work.
Ascertain from the senior watchkeeper if it is okay to start work, isolate the valves then commence work.
In conjunction with the senior watchkeeper and electrician, isolate valves, electrical supply, automatics and post 'Do not operate' signs before commencing work.
Isolate the suction and delivery valves then inform the electrician that you are starting work.

Why is it necessary to use the vacuum pump after major overhaul of the reefer system?

Not necessary.
In order to reduce the pressure in the system before start-up.
To evacuate air and water out of the system in order to prevent problem during operation.
To make underpressure in the reefer system in order to get the freon liquid easy back to the system.

When an overhaul is completed and the compressor is going to be started for a test run, it is important that we:

What is the meaning of the term 'valve clearance'?

The clearance between the rocker arm and valve pushrod.
The clearance between the rocker arm and camshaft pushrod.
The clearance between valve spindle disc and seat.
The clearance between the rocker arm and valve pushrod in either warm or cold state

What corrosion prevention measures should be taken if a boiler is to be out of service for an extended period?

The meaning of lapping a valve and valve seat is:

Why do many engine makers recommend to grind the valve spindle sealing surface with a half degree difference to the valve seat?

To avoid sticking between valve and seat during high load operation
To compensate for the heat expansion
To minimize heat transfer between seat and housing.
To improve the sealing surface between valve and seat during operation of the engine (compensate for the bending of the valve disc caused by combustion pressure)

Some engine manufacturers recommend that washing of the compressor side is not carried out. Is this due to:

Greasy sludge from the compressor sticking between the fins in the air coolers, necessitating extra cleaning of these.
The thermal shock exhibited by the vanes.
Large volumes of water being carried over into the cylinders of the engine.
The nozzle ring becoming corroded.

When overhauling the cylinder covers on a modern 4-stroke engine, is it important not to interchange inlet and exhaust valves?

Why do many engine makers recommend to grind the valve spindle sealing surface with a half degree difference to the valve seat?

To improve the sealing surface between valve and seat during operation of the engine (compensate for the bending of the valve disc caused by combustion pressure).
To compensate for the heat expansion.
To minimize heat transfer between seat and housing.
To avoid sticking between valve and seat during high load operation.

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