Marine Technician Engine Systems Flashcards
7 cards from real MTC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Marine Technician Engine Systems flashcards as text
On a marine gasoline engine, what symptom typically indicates a failing water pump impeller?
Answer: Engine overheating and reduced raw water flow
A worn or broken impeller fails to pump sufficient raw water, reducing cooling capacity and causing the engine to overheat.
Which tool is used to check crankshaft end play on a marine engine?
Answer: Dial indicator
A dial indicator mounted against the crankshaft flange measures axial (end) play when the crank is pushed fore and aft.
What does a persistently low oil pressure reading on a marine engine most likely indicate?
Answer: Worn main or rod bearings allowing oil to bypass
Worn crankshaft or rod bearings increase clearance, allowing oil to escape the pressurized circuit faster than the pump can maintain pressure.
A technician performing a compression test on a gasoline inboard finds one cylinder reading 90 psi while others read 150 psi. What is the most likely diagnosis?
Answer: Worn or damaged piston rings or valves on that cylinder
A single low compression reading points to a sealing problem in that cylinder—most commonly worn rings, a burned valve, or a leaking head gasket.
What is the correct procedure when checking valve clearance on a marine diesel engine?
Answer: Check with the cylinder at TDC on the compression stroke and the engine cold or at specified temperature
Valve clearance is measured with the piston at TDC on compression (both valves closed) at the temperature specified by the manufacturer.
Which type of marine engine cooling system uses antifreeze and a heat exchanger to transfer heat to raw seawater?
Answer: Closed freshwater cooling (heat exchanger cooling)
A closed freshwater system circulates antifreeze through the engine and transfers heat via a heat exchanger to raw water that is then discharged overboard.
What is the primary reason marine engines require more frequent zincs (sacrificial anodes) inspection than engine internal service?
Answer: Galvanic corrosion rate depends on water salinity, temperature, and dissimilar metal contact
Galvanic corrosion intensity varies with environmental conditions, so anode consumption can be rapid or slow depending on salinity, temperature, and metal pairings present.