Marine Technician Fuel & Cooling 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 Fuel & Cooling Systems flashcards as text
What is the primary purpose of a heat exchanger in a marine closed-cooling system?
Answer: To transfer heat from engine coolant to raw water without mixing the two
A heat exchanger allows engine coolant to give up heat to raw water while keeping the two fluids separated, protecting internal passages from corrosion and scale.
A two-stroke marine outboard engine exhibits fuel starvation at wide-open throttle but runs fine at idle. The MOST likely cause is:
Answer: A restricted high-speed main jet or fuel filter
High-speed fuel starvation points to a restricted main jet or inline fuel filter that cannot supply adequate flow under full load demand.
When pressure-testing a marine cooling system, what is the recommended maximum test pressure for most marine engines?
Answer: 15–18 psi
Most marine cooling systems are pressure-tested to 15–18 psi, matching the pressure cap rating and safely revealing leaks without damaging hoses or fittings.
A raw-water impeller made of neoprene runs dry for 30 seconds. What is the expected result?
Answer: Premature vane cracking and possible total impeller failure
Neoprene impellers rely on the pumped water for lubrication; even 30 seconds of dry running causes vane cracking or breakage that restricts cooling flow.
In a marine fuel injection system, what role does the fuel pressure regulator play?
Answer: It maintains constant fuel pressure across the injector rail regardless of engine load
The fuel pressure regulator holds a steady rail pressure (referenced to manifold vacuum on some systems) so injector flow depends solely on pulse width, not pressure variation.
Which symptom BEST indicates a stuck-open marine engine thermostat?
Answer: Engine runs continuously below normal operating temperature
A stuck-open thermostat allows coolant to circulate freely before reaching operating temperature, causing the engine to run chronically cold and inefficiently.
What is the function of an anti-siphon valve installed on a marine fuel system?
Answer: It prevents fuel from siphoning from the tank into the engine compartment if a line is broken
An anti-siphon valve opens only when the fuel pump is running, preventing gravity-fed fuel flow into the bilge if a downstream line fails, reducing fire risk.