Question 1

crank case inspection

Accepted Answer

A crankcase inspection reads oil, metal and bolts: colour, smell and particles first, hotspots and security second. Oil: colour not black, no diesel, heavy-oil or ammonia smell, no sliminess — plus white-metal particles in the sump. Metal: bluish-dark patches mark hotspots; check crank-web slip, floating con rod, crosshead guides and bedplate cracks. Security: bottom-end bolt lock wires and washers, wire mesh intact, relief-door springs free. Never open hot: ventilate, test for mist, enter only cool with starting air locked and turning gear engaged. Surveyor follow-up: oil smells of diesel with level rising — inspect deeper or find the leak first, and where?

Question 2

Why centrifugal pump has wear ring?

Accepted Answer

Wear rings are the cheap sacrificial clearance: they let the impeller spin close to the casing without metal-to-metal wear. A tight clearance between impeller and casing stops discharge leaking back to suction. Some erosion is certain, so replaceable rings on impeller and casing take the wear instead of the parts themselves. As clearances open, leakage grows and efficiency falls — renew the rings, not the pump. Sketch it as casing, volute, impeller, shaft, gland and the two rings holding the running gap. Surveyor follow-up: discharge falling with clearances double the book figure — rings, impeller or speed, and what do you measure first?

Question 3

how remove broken stud

Accepted Answer

Broken studs come out by grip, drill or weld: extractor first, left-hand tap second, welded nut when nothing else bites. Soak with penetrating oil and heat the surround, never the stud alone, then try the extractor. Drill true down the centre and cut a left-hand thread with an anticlockwise tap that tightens itself out. With no purchase left, weld a nut or bar onto the stump and turn it out with a spanner. Last resort is metal disintegration or drilling oversize and re-tapping — measure twice, drill once. Surveyor follow-up: extractor snaps inside the stud — drill through it or spark-erode it, and why?

Question 4

Types of scavenging?

Accepted Answer

Scavenging sweeps exhaust with fresh air three ways: loop over the crown, cross under the cover, uniflow straight up. Loop: air loops over the piston crown and out ports on the same liner side above the scavenge ports. Cross: air rises one side, sweeps under the cover and falls out ports on the far side. Uniflow: air drives straight up the bore and out through head ports or valves — the modern large-engine choice. Sketch all three with arrows: ports, cover and valves decide which type the engine breathes. Surveyor follow-up: your engine loop, cross or uniflow — point at the ports and prove it.

Question 5

why hp cut out

Accepted Answer

High-pressure cutout guards the compressor: over-pressure on discharge trips it, hand reset restarts it. Bellows between discharge and condenser feel the pressure against a spring set by the adjusting screw. Past the set discharge pressure the switch arm drops and stops the compressor before joints part. Low-pressure and oil-differential switches back it up — LP near 1 bar, oil differential near 1.2 bar, both hand reset. After any trip find the cause — fouled condenser, overcharge, blocked water — then reset deliberately. Surveyor follow-up: HP trips repeatedly with the condenser clean — overcharge, air or water flow, and what gauge proves it?

Question 6

for each of the following describe the effect of dirty or restricted

Accepted Answer

Dirt throttles every circuit the same way: pressure drops, temperatures climb, protection trips — name the medium, then the effect. Dirty air filters drop suction pressure and delivery temperature with cooler manifold air, not hotter. Restricted cooling cuts flow and lifts outlet temperatures until high-temperature alarms and trips act. Choked fuel filters starve injection with falling pressure, smoke and lost power. Fouled lube strainers drop bearing pressure toward the trip while temperatures climb together. Surveyor follow-up: delivery pressure down with suction pressure also down — filter, cooler or pump, and what proves it?

Question 7

state the purpose of fuel pump on low speed two stroke engine

Accepted Answer

The fuel pump meters, pressurises and times every shot: constant nozzle pressure across the injection window at any speed. Builds and holds pressure before the nozzle through the whole injection period for even atomisation. Varies effective stroke for load while injection pressure and admission rate stay near constant. Times by cam-peak position with plunger-height trim — raise the plunger for earlier cut-off, lower for later. Low-speed running injects inside maximum plunger acceleration so load swings never starve the nozzle. Surveyor follow-up: pressure sagging at low load with timing correct — plunger, valves or cam, and what proves it?

Question 8

With a flow chart show and explain the process involved in fuel treatment to achieve desired quality

Accepted Answer

Draw settling to service through heat, spin and filter: tanks settle, purifiers spin, heaters thin, filters polish. Settling tanks drop water and sludge by gravity with drains run daily. Centrifugal purifiers heated near 98 degrees cut viscosity toward 24 cSt for separation. Heaters with viscometer steam control land 10–14 cSt at the injector for atomisation. Fine filters guard the pumps with sludge to the heated sludge tank for disposal — soluble vanadium and sodium pass through regardless. Surveyor follow-up: draw the flow from bunker tank to injector — where do purifier, heater and viscometer sit?

Question 9

Air, pressure low on

Accepted Answer

Low air with low compression means the cylinders starve together: turbocharger, rings, liner and cooler in that order. Fouled turbocharger and clogged scavenge ports cut delivery pressure to every unit at once. Broken rings leaking past compression bleed charge mass and pressure together. Worn liners and leaking coolers join the same story with rising exhaust and falling power. Prove with scavenge pressure against trial figures, then compression diagrams per unit before opening. Surveyor follow-up: one unit low with the rest normal — common air or that cylinder, and what diagram proves it?

Question 10

How the indicator power of an engine can be measured using indicator instrument, give the procedure with simple sketch of instrument used

Accepted Answer

Indicate power by diagram area: blow through the cock, hook the drum, draw power, compression and draw cards, planimeter the area. Prove the instrument first — piston drop-tested, drum free, pencil light, cock blown clear two or three firing strokes. Fit the rated spring for expected peak pressure and draw power cards per cylinder without overheating the instrument. Cut fuel for the compression line on a clear drum spot, then draw, compression and light-spring cards complete the set. Measure area by planimeter for indicated power per unit; clean, grease hot and log every card. Surveyor follow-up: power card area small with compression normal — fuel, timing or load, and what proves it?

Motor (Function 4b) — Most Asked Questions

General Marine Engineering

Crankshaft / Bearing / Cylinder

Ship Types & Cargo

Boiler (motor)

Certificates & Statutory Survey

Piping & Hydraulics

Engine Room - General

Fuel Oil System

Pumps (motor)

Lubrication System

Batteries & Emergency Power

Engine Room General (motor)

Auxiliary Engine / Generator

Engine Room Auxiliaries (MEP)

Auxiliary Machinery - ER

Gas Cylinder & CO2 Room Safety

Main Engine

Refrigeration Plant

Bulkheads, Pipes & Fittings (General)

Turbocharger / Supercharger

Stern Tube / Propeller

Ship Structure - Frames & Floors

Cooling Water System

Air Compressor (motor)