ABYC Practice Questions with correct
answers 2025
FALSE. End fittings introduce the possibility of high resistance. TE-4, Conductors - ANSWER A
sailboat's rigging is considered a reliable path to ground for lightning? T/F?
Spark igntion Diesel Study Guide, Chapter 1 - ANSWER Gasoline engines use what kind of
ignition?
Compression ignition Diesel Study Guide, Chapter 1 - ANSWER Diesel engines use what kind of
ignition?
Gasoline engines Diesel Study Guide, Chapter 1 - ANSWER Spark ignition are what kind of
engines?
Diesel engines Diesel Study Guide, Chapter 1 - ANSWER Compression ignition are what kind of
engines?
750 degrees or more Diesel Study Guide, Chapter 1 - ANSWER How hot must a atomized diesel
get before combustion?
TRUE, denser air has more oxygen molecules per cubic foot Diesel Study Guide, Chapter 1 -
ANSWER Cooler air is denser than ambient temperature? T/F?
A. The intake stroke only brings air into the cylinder. Diesel Study Guide, Chapter 1 - ANSWER
"One of the primary differences between the gasoline-fueled engine four-stroke cycle and the
diesel four-stroke cycle is:
A. The intake stroke only brings air into the cylinder.
,B. The compression ratio of the diesel engine is much lower than the same sized gasoline
engine.
C. Fuel gets atomized by the high heat with a diesel engine.
D. The diesel fuel is more volatile than the gasoline."
Manometer Diesel Study Guide, Chapter 2 - ANSWER What is the tool to check engine back-
pressure?
TRUE Diesel Study Guide, Chapter 2 - ANSWER When checking engine back-pressure, the engine
must be under load to get a valid reading. T/F?
C. 200mV Diesel Study Guide, Chapter 2, pg 23 - ANSWER "When choosing materials, we want
them to be as close as possible on the Galvanic Series. What is the recommended separation of
corrosion potential?
A. 200V
B. 2000mV
C. 200mV
D. 2V"
D. prevent excessive exhaust back-pressure. Diesel Study Guide, Chapter 2 - ANSWER "In setting
up a piping system for exhaust gases, the number of sharp bends should be kept to a minimum
to:
A. raise exhaust gas temperature.
B. permit use of a larger diameter pipe.
C. eliminate the need for a silencer.
D. prevent excessive exhaust back-pressure."
, C. Siphon break. Diesel Study Guide, Chapter 2 - ANSWER "An engine equipped with an exhaust-
mixing elbow is installed below the waterline. What device must be installed in the raw water
discharge hose ahead of the mixing elbow?
A. Manometer.
B. Flow diverter.
C. Siphon break.
D. Flapper valve."
B. Technician B. Diesel Study Guide, Chapter 2 - ANSWER "Upon inspection of the wet exhaust
system, the technician notices that the exhaust hose is burned near the elbow. Technician A
says that replacing the hose will correct the problem. Technician B says that the problem is most
likely with the cooling system. Which technician is correct?
A. Technician A.
B. Technician B.
C. Both technicians are correct.
D. Neither technician is correct."
A clear hose Diesel Study Guide, Chapter 3 - ANSWER What is a good trick to see if a seacock is
suffering from aeration?
B. Milky Diesel Study Guide, Chapter 3 - ANSWER "Water in oil will cause the oil to look:
A. Dark black
B. Milky
C. Translucent
D. Fluffy brown"
False. Diesel Study Guide, Chapter 3 - ANSWER Always use Teflon tape on the threads of pencil
zincs. T/F?
answers 2025
FALSE. End fittings introduce the possibility of high resistance. TE-4, Conductors - ANSWER A
sailboat's rigging is considered a reliable path to ground for lightning? T/F?
Spark igntion Diesel Study Guide, Chapter 1 - ANSWER Gasoline engines use what kind of
ignition?
Compression ignition Diesel Study Guide, Chapter 1 - ANSWER Diesel engines use what kind of
ignition?
Gasoline engines Diesel Study Guide, Chapter 1 - ANSWER Spark ignition are what kind of
engines?
Diesel engines Diesel Study Guide, Chapter 1 - ANSWER Compression ignition are what kind of
engines?
750 degrees or more Diesel Study Guide, Chapter 1 - ANSWER How hot must a atomized diesel
get before combustion?
TRUE, denser air has more oxygen molecules per cubic foot Diesel Study Guide, Chapter 1 -
ANSWER Cooler air is denser than ambient temperature? T/F?
A. The intake stroke only brings air into the cylinder. Diesel Study Guide, Chapter 1 - ANSWER
"One of the primary differences between the gasoline-fueled engine four-stroke cycle and the
diesel four-stroke cycle is:
A. The intake stroke only brings air into the cylinder.
,B. The compression ratio of the diesel engine is much lower than the same sized gasoline
engine.
C. Fuel gets atomized by the high heat with a diesel engine.
D. The diesel fuel is more volatile than the gasoline."
Manometer Diesel Study Guide, Chapter 2 - ANSWER What is the tool to check engine back-
pressure?
TRUE Diesel Study Guide, Chapter 2 - ANSWER When checking engine back-pressure, the engine
must be under load to get a valid reading. T/F?
C. 200mV Diesel Study Guide, Chapter 2, pg 23 - ANSWER "When choosing materials, we want
them to be as close as possible on the Galvanic Series. What is the recommended separation of
corrosion potential?
A. 200V
B. 2000mV
C. 200mV
D. 2V"
D. prevent excessive exhaust back-pressure. Diesel Study Guide, Chapter 2 - ANSWER "In setting
up a piping system for exhaust gases, the number of sharp bends should be kept to a minimum
to:
A. raise exhaust gas temperature.
B. permit use of a larger diameter pipe.
C. eliminate the need for a silencer.
D. prevent excessive exhaust back-pressure."
, C. Siphon break. Diesel Study Guide, Chapter 2 - ANSWER "An engine equipped with an exhaust-
mixing elbow is installed below the waterline. What device must be installed in the raw water
discharge hose ahead of the mixing elbow?
A. Manometer.
B. Flow diverter.
C. Siphon break.
D. Flapper valve."
B. Technician B. Diesel Study Guide, Chapter 2 - ANSWER "Upon inspection of the wet exhaust
system, the technician notices that the exhaust hose is burned near the elbow. Technician A
says that replacing the hose will correct the problem. Technician B says that the problem is most
likely with the cooling system. Which technician is correct?
A. Technician A.
B. Technician B.
C. Both technicians are correct.
D. Neither technician is correct."
A clear hose Diesel Study Guide, Chapter 3 - ANSWER What is a good trick to see if a seacock is
suffering from aeration?
B. Milky Diesel Study Guide, Chapter 3 - ANSWER "Water in oil will cause the oil to look:
A. Dark black
B. Milky
C. Translucent
D. Fluffy brown"
False. Diesel Study Guide, Chapter 3 - ANSWER Always use Teflon tape on the threads of pencil
zincs. T/F?
