ABYC Diesel Engine Certification-
Basic Diesel Principles and Exhaust
Systems 2025 EXAM
which type of engine pulls ventilation from the bottom and exhausts warm air through
the top? - Answer-Diesel engine
Which type of engine pulls cool ventilation from the top and exhausts warm air through
the bottom? - Answer-Gasoline Engine
the fuel fill (cap) should be placed atleast 15-inches from the first point of entry (i.e. the
very tip of the vent scoop) - true or false? - Answer-true (refer to photo on page 10)
For vessels greater than 26 (and ALL SAILBOATS) feet the lowest point of ventilation
must be placed - Answer-above the maximum heeled water line
For power boats less than 26 feet, the lowest ventilation point must be higher than the -
Answer-static float plane line based on max persons/weight capacity
True or false: diesel engine contains carbon monoxide - Answer-true
What tool is used to check back-pressure of a new or modified engine installation? -
Answer-Manometer
Water lift mufflers with too much lift for the engine, bends or elbows in the system, or
exhaust diameter that's too small or a faulty muffler (silencer) can all cause.... - Answer-
Excessive exhaust back-pressure
The exhaust system will be (x) to the hull interior - Answer-gas tight
The exhaust riser must be installed.... - Answer-with a siphon break that is 18 inches
above max heeled water line
what aids in pushing the water up and out of the exhaust riser (leading out of the boat) -
Answer-exhaust gas pressures push the water through and out
What part of the exhaust system commonly rusts out and becomes a point of restricted
flow? - Answer-the metal-lined exhaust riser hose
Over-cranking during problematic engine starting may cause .... - Answer-excessive raw
salt water intake into the water-lift chamber
Basic Diesel Principles and Exhaust
Systems 2025 EXAM
which type of engine pulls ventilation from the bottom and exhausts warm air through
the top? - Answer-Diesel engine
Which type of engine pulls cool ventilation from the top and exhausts warm air through
the bottom? - Answer-Gasoline Engine
the fuel fill (cap) should be placed atleast 15-inches from the first point of entry (i.e. the
very tip of the vent scoop) - true or false? - Answer-true (refer to photo on page 10)
For vessels greater than 26 (and ALL SAILBOATS) feet the lowest point of ventilation
must be placed - Answer-above the maximum heeled water line
For power boats less than 26 feet, the lowest ventilation point must be higher than the -
Answer-static float plane line based on max persons/weight capacity
True or false: diesel engine contains carbon monoxide - Answer-true
What tool is used to check back-pressure of a new or modified engine installation? -
Answer-Manometer
Water lift mufflers with too much lift for the engine, bends or elbows in the system, or
exhaust diameter that's too small or a faulty muffler (silencer) can all cause.... - Answer-
Excessive exhaust back-pressure
The exhaust system will be (x) to the hull interior - Answer-gas tight
The exhaust riser must be installed.... - Answer-with a siphon break that is 18 inches
above max heeled water line
what aids in pushing the water up and out of the exhaust riser (leading out of the boat) -
Answer-exhaust gas pressures push the water through and out
What part of the exhaust system commonly rusts out and becomes a point of restricted
flow? - Answer-the metal-lined exhaust riser hose
Over-cranking during problematic engine starting may cause .... - Answer-excessive raw
salt water intake into the water-lift chamber
