ABYC DIESEL CERTIFICATION
2025 EXAM QUESTIONS AND
ANSWERS
Which fuel indicators are permitted by abyc standards h33 - Answer-Dipstick, electronic
center, sight gauge
a customer complains of white smoke only when the engine is cold. Technician a says
this could be caused by a faulty preheat device. Technician b says the white smoke is
caused by partially vaporized fuel. Who is right - Answer-Both techs
during a sea trial with mechanical Governor engines do you find the port engine will not
come up to full load, your notes show the high idle on the port engine was 300 RPM
below specs. The most likely answer is - Answer-Throttle linkage adjustment
You are troubleshooting a sudden oil leak on a low our mechanical engine, the
customer complains that the dipstick is being pushed out of the block and oil is leaking
from the front crankshaft seal. The most likely answer is - Answer-Plugged crankcase
breather
The owner is complaining of low power. On a sea trial under full load you measure
exhaust gas temperature and boost pressure. You explain to the owner you feel he
might have a cylinder not putting out full power because - Answer-The boost and
temperature are both below specification
the owner is complaining of low top end speed. On a sea trial under a full load you
measure exhaust gas temperature and boost pressure. You explain to the owner you
feel the engine is overloaded based on - Answer-The boost is lower than specification
and the temperature is above specification
The operator of a diesel boat has a complaint of low power and no smoke the technician
should first check the - Answer-Fuel pressure
Add high-speed the raw water pressure shows heavy fluctuation as indicated on a
pressure gauge. A possible cause would be - Answer-Debris in the sea water pick up
A ruptured oil cooler core may result in - Answer-Water in the oil system or oil in the
water system
, Which factors must be considered when installing adjusting transmission shift - Answer-
Centering and fold travel, idle speed and full throttle
Diesel engines are what percent more efficient in fuel economy compared to gasoline -
Answer-10 to 15%
The typical voltage drop on voltage sensing battery combiners is - Answer-0.7
What is the ideal amounts of drops per minute for a stuffing box - Answer-1 to 3
protective guards are required on exhaust systems whenever persons or gear might
come in contact with the exhaust system where the temperature exceeds - Answer-200
degrees Fahrenheit
The middle on the inside diameter of a diesel fuel filter system shall be - Answer-1 and
1/8
What tool can be used to identify misfiring diesel engine cylinder - Answer-Infrared heat
gun
ABYC states that a failure occurs with the shaft seal while operating at low speeds no
more than how many gallons per minute can enter - Answer-2 gallons
What are the most common organisms that can live in diesel tanks - Answer-Bacteria,
mold fungus
In respect to a water lift systems, is necessary to have a what? In the event the engine
will not crank to prevent water back into the cylinders - Answer-Drain
A turbocharger oil seal failure can cause - Answer-Engine to run away
The owner complains that the throttle handle will not hold position. What adjustment
Mike correct this problem? - Answer-Throttle friction adjustment at the control head
Gel cell batteries shall not be charged at more than how many volts - Answer-14.1 volts
Electrolyte loss and batteries is most often caused by - Answer-System overcharging
A fully charged battery at rest will show a minimum of how many volts - Answer-12.6
volts
Battery switches are required for any battery when - Answer-Over 800cca
When using a hydrometer any cell less than how many points is considered a bad cell -
Answer-0.50 points
2025 EXAM QUESTIONS AND
ANSWERS
Which fuel indicators are permitted by abyc standards h33 - Answer-Dipstick, electronic
center, sight gauge
a customer complains of white smoke only when the engine is cold. Technician a says
this could be caused by a faulty preheat device. Technician b says the white smoke is
caused by partially vaporized fuel. Who is right - Answer-Both techs
during a sea trial with mechanical Governor engines do you find the port engine will not
come up to full load, your notes show the high idle on the port engine was 300 RPM
below specs. The most likely answer is - Answer-Throttle linkage adjustment
You are troubleshooting a sudden oil leak on a low our mechanical engine, the
customer complains that the dipstick is being pushed out of the block and oil is leaking
from the front crankshaft seal. The most likely answer is - Answer-Plugged crankcase
breather
The owner is complaining of low power. On a sea trial under full load you measure
exhaust gas temperature and boost pressure. You explain to the owner you feel he
might have a cylinder not putting out full power because - Answer-The boost and
temperature are both below specification
the owner is complaining of low top end speed. On a sea trial under a full load you
measure exhaust gas temperature and boost pressure. You explain to the owner you
feel the engine is overloaded based on - Answer-The boost is lower than specification
and the temperature is above specification
The operator of a diesel boat has a complaint of low power and no smoke the technician
should first check the - Answer-Fuel pressure
Add high-speed the raw water pressure shows heavy fluctuation as indicated on a
pressure gauge. A possible cause would be - Answer-Debris in the sea water pick up
A ruptured oil cooler core may result in - Answer-Water in the oil system or oil in the
water system
, Which factors must be considered when installing adjusting transmission shift - Answer-
Centering and fold travel, idle speed and full throttle
Diesel engines are what percent more efficient in fuel economy compared to gasoline -
Answer-10 to 15%
The typical voltage drop on voltage sensing battery combiners is - Answer-0.7
What is the ideal amounts of drops per minute for a stuffing box - Answer-1 to 3
protective guards are required on exhaust systems whenever persons or gear might
come in contact with the exhaust system where the temperature exceeds - Answer-200
degrees Fahrenheit
The middle on the inside diameter of a diesel fuel filter system shall be - Answer-1 and
1/8
What tool can be used to identify misfiring diesel engine cylinder - Answer-Infrared heat
gun
ABYC states that a failure occurs with the shaft seal while operating at low speeds no
more than how many gallons per minute can enter - Answer-2 gallons
What are the most common organisms that can live in diesel tanks - Answer-Bacteria,
mold fungus
In respect to a water lift systems, is necessary to have a what? In the event the engine
will not crank to prevent water back into the cylinders - Answer-Drain
A turbocharger oil seal failure can cause - Answer-Engine to run away
The owner complains that the throttle handle will not hold position. What adjustment
Mike correct this problem? - Answer-Throttle friction adjustment at the control head
Gel cell batteries shall not be charged at more than how many volts - Answer-14.1 volts
Electrolyte loss and batteries is most often caused by - Answer-System overcharging
A fully charged battery at rest will show a minimum of how many volts - Answer-12.6
volts
Battery switches are required for any battery when - Answer-Over 800cca
When using a hydrometer any cell less than how many points is considered a bad cell -
Answer-0.50 points
