Millwright – Engines: Questions With Solutions
What is the purpose of a coolant bypass tube when referring to
thermostats? ✔️Ans - To reduce warm-up time and prevent cylinder
head from over heating
What must be done to the air/fuel mixture on a gasoline system before it
enters the cylinders? ✔️Ans - The carburetor vaporizes the liquid
gasoline and mixes it with the incoming air to provide the correct air-fuel
mixture.
Running __________ = not enough power, increase in temperature (like a
turbo boost). The air fuel ratio will change, eg) from 14:1 to 16:1. ✔️Ans -
too lean (more air)
After performing any work on a diesel fuel system you must, ___________
before running. (filters, injectors, injector pump, etc.) ✔️Ans - bleed all
the air out
The purpose of __________ is to atomize the fuel and spray it into the cylinder
at the correct time. ✔️Ans - injectors
What is the main difference between gas and diesel engines? ✔️Ans -
Because of the high compression ratio (16:1 - 20:1), this gives a high air
temperature which can ignite the fuel without a spark.
How is a diesel engine timed?
The injection pump delivers fuel under high pressure at the correct
moment to the injectors.
Running ___________ =high emissions (O2 sensors), high exhaust
temperatures. The air:fuel ratio will change, eg) from 14:1 to 12:1 ✔️Ans
- too rich (more fuel)
What is the purpose of a vaporizer on an LPG system?
V ✔️Ans - vaporize the liquid propane to a gas by a pressure drop and by
heating the liquid with warm engine coolant.
, What are some causes of detonation? ✔️Ans - Low octane fuels, Timing
set to early, Lean fuel mixtures, Improper cooling.
Ideally you should place the rain gaps ✔️Ans - 180* apart and 45* to the
wrist pin
Spark plug is threaded into the?
A. Cylinder
B. Block
C. Combustion chamber
D. Piston ✔️Ans - C. Combustion chamber
To be sure that lifting attachment does not damage engine accessories it is
best to use?
A. Spreader bar
B. Equalizer
C. Softeners
D. Bridal ✔️Ans - Spreader bar
When you take an exhaust or intake manifold pressure reading with a
monometer you must?
A. Run idle speed
B. Half speed
C. At full load
At full speed unloaded ✔️Ans - C. At full load
What is the name of the engine component that controls the opening and
closing of the valves? ✔️Ans - Camshaft
The _________ may push directly on the valve stem (OHC), or may push on
the valve through a lifter, pushrod and rocker arm assembly (in block
design) to control the opening and closing of the vavles in a engine. ✔️Ans
- camshaft
What is the purpose of the rocker arm? ✔️Ans - Are moved by the
pushrods to operate the valves.
What is the purpose of the pushrod? ✔️Ans - It transmits the camshaft
motion from the lifter to the rocker arm.
What is the purpose of a coolant bypass tube when referring to
thermostats? ✔️Ans - To reduce warm-up time and prevent cylinder
head from over heating
What must be done to the air/fuel mixture on a gasoline system before it
enters the cylinders? ✔️Ans - The carburetor vaporizes the liquid
gasoline and mixes it with the incoming air to provide the correct air-fuel
mixture.
Running __________ = not enough power, increase in temperature (like a
turbo boost). The air fuel ratio will change, eg) from 14:1 to 16:1. ✔️Ans -
too lean (more air)
After performing any work on a diesel fuel system you must, ___________
before running. (filters, injectors, injector pump, etc.) ✔️Ans - bleed all
the air out
The purpose of __________ is to atomize the fuel and spray it into the cylinder
at the correct time. ✔️Ans - injectors
What is the main difference between gas and diesel engines? ✔️Ans -
Because of the high compression ratio (16:1 - 20:1), this gives a high air
temperature which can ignite the fuel without a spark.
How is a diesel engine timed?
The injection pump delivers fuel under high pressure at the correct
moment to the injectors.
Running ___________ =high emissions (O2 sensors), high exhaust
temperatures. The air:fuel ratio will change, eg) from 14:1 to 12:1 ✔️Ans
- too rich (more fuel)
What is the purpose of a vaporizer on an LPG system?
V ✔️Ans - vaporize the liquid propane to a gas by a pressure drop and by
heating the liquid with warm engine coolant.
, What are some causes of detonation? ✔️Ans - Low octane fuels, Timing
set to early, Lean fuel mixtures, Improper cooling.
Ideally you should place the rain gaps ✔️Ans - 180* apart and 45* to the
wrist pin
Spark plug is threaded into the?
A. Cylinder
B. Block
C. Combustion chamber
D. Piston ✔️Ans - C. Combustion chamber
To be sure that lifting attachment does not damage engine accessories it is
best to use?
A. Spreader bar
B. Equalizer
C. Softeners
D. Bridal ✔️Ans - Spreader bar
When you take an exhaust or intake manifold pressure reading with a
monometer you must?
A. Run idle speed
B. Half speed
C. At full load
At full speed unloaded ✔️Ans - C. At full load
What is the name of the engine component that controls the opening and
closing of the valves? ✔️Ans - Camshaft
The _________ may push directly on the valve stem (OHC), or may push on
the valve through a lifter, pushrod and rocker arm assembly (in block
design) to control the opening and closing of the vavles in a engine. ✔️Ans
- camshaft
What is the purpose of the rocker arm? ✔️Ans - Are moved by the
pushrods to operate the valves.
What is the purpose of the pushrod? ✔️Ans - It transmits the camshaft
motion from the lifter to the rocker arm.
