AGR 170 Agricultural Technology – Small Engine Mechanics Practice Exam

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• How can additional power be created without increasing cylinder size?
• Which of the following octane ratings is the highest among the options?
• A horizontal crankcase configuration is typically found in which type of small-engine equipment?
• A ventilation system or device that allows excessive crankcase pressure to escape?
• What are the signs of a slipping drive belt in a small engine drive system and how is it corrected?
• The heat value of fuel is measured in units of ________.
• Define valve lash and explain why it must be checked on a cold engine.
• In engine terminology, what does the acronym TDC stand for?
• Which of the following is not a common air filter type used on small engines?
• In float height setting, measuring against a specified reference ensures what?
• Which component lifts valves open and closed?
• Which term describes the process of burning the fuel-air mixture?
• How many strokes are involved in a four-stroke engine cycle?
• The component that powers the spark plug is called the what?
• When storing an engine for an extended period, which fuel-handling action is recommended?
• What is the proper sequence for adjusting idle and main mixture on a carburetor?
• What practice helps prevent ethanol-related varnish buildup in small engines?
• How do you set the float height on a float-type carburetor?
• What is the term for the engine's main rotating shaft that converts reciprocating motion to rotary motion?
• Describe how to perform a leak-down test and interpret the results.
• Which two main ignition systems are used on modern engines?
• What is the typical spark plug gap range in inches?
• Which statement best describes the difference between an engine and a motor?
• In a four-stroke engine, which stroke is the power stroke?
• Which engine cycle includes the intake, compression, power, and exhaust strokes?
• What is the primary function of a turbocharger or blower in an engine?
• Which PPE is recommended when handling gasoline or working on engines?
• Which of the following is one of the eight systems in a small engine that provides lubrication?
• Outline the steps to perform a compression test and what the readings indicate.
• Bottom Dead Center stands for which piston position?
• Industry definitions classify a small engine as having one to four cylinders and at most how many horsepower?
• Which valve allows exhaust gases to exit the cylinder?
• Which oil-related condition can contribute to overheating in an air-cooled engine?
• What is involved in a basic engine rebuild evaluation?
• Which component connects the piston to the crankshaft?
• Which engine component sits above the piston and houses the combustion chamber, as well as the intake and exhaust valves and ports?
• How would you detect a restricted air intake and what problems would it cause?
• Which term describes the burning of the fuel-air mixture in an engine?
• What is the purpose of a primer/primer bulb on some engines?
• Where does the combustion take place (the piston is housed)?
• A horizontal crankcase orientation is commonly found in which equipment group?
• Which component converts the linear motion of a piston into rotational motion that drives the crankshaft?
• What does OHV stand for in engine terminology?
• What is the movable part in the cylinder that is forced into motion by the explosion of fuel?
• Diesel compression ratio range according to the material?
• How many main systems are typically identified in a small engine?
• What is the proper reason to re-check idle and main adjustments after driving the engine?
• Gasoline compression ratio is typically in which range according to the material?
• Controls the cams that control the intake and exhaust valves.
• A two-stroke engine completes a power cycle in how many strokes?
• What is the role of cooling fin cleaning on air-cooled engines and how can you tell if the engine is overheating?
• Name the two main ignition system configurations found on small engines and a basic method to test for spark.
• Naturally aspirated engines operate at what pressure?
• White smoke from the exhaust is a sign of what condition in a small engine?
• How do you perform a basic spark plug condition check and interpret deposits?
• What is the piece of casting bolted to the top of the engine cylinder called?
• What could cause a small engine to stumble or die during acceleration, and how would you troubleshoot?
• Compare recoil starting and electric starting systems and name a key maintenance item for each.
• What is the purpose of a compression release mechanism on many small engines, and when is it used?
• How do you adjust valve lash on a typical small engine with adjustable rocker arms?
• What is a typical oil-change interval for most small gasoline engines?
• A carburetor with a clogged idle jet will most likely cause which symptom?
• Which statement correctly pairs fuel properties with their ratings?
• Which of the following is one of the eight systems in a small engine that helps regulate engine speed?
• Which parameter describes how effectively an engine fills its cylinders with air-fuel mixture?
• Which company is credited as the first to produce small engines in the 1920s?
• Describe a safe, step-by-step procedure to clean a clogged carburetor without a complete rebuild.
• A device that converts chemical energy (from gasoline) into heat energy (from compression) into mechanical energy to perform work is called what?
• Diesel engine compression ratio typical range is which of the following?
• A heavy wheel fastened to one end of the crankshaft to improve running quality of the engine is called?
• What is the purpose of kill switches and safety interlocks on small engines?
• Which of the following is NOT listed as a possible cause of low compression?
• Volumetric Efficiency is best described as which of the following?
• What is a valve seat and why must it seal properly for engine performance?
• How would you diagnose a fuel starvation issue that presents differently when starting cold versus when warm?
• The compression ratio is defined as the ratio of which two cylinder volumes?
• Which component rotates twice during a four-stroke cycle?
• Gasoline should be used within how many days to ensure freshness for small engines?
• In a four-stroke engine, which term is not one of the four strokes?
• What is the most important maintenance action to keep an air cooling system working effectively?
• Gasoline compression ratio is typically within which range?
• How does a diaphragm carburetor operate differently from a float-type carburetor, and what parts should be inspected?
• What part powers the spark plug?
• Which term describes the early historical name for automobiles?
• What is the typical spark plug gap for many small engines, and how is it adjusted?
• In an overhead valve engine, where is the camshaft located?
• What is the common horsepower range used to define small engines?
• Which system is responsible for bringing fuel to the engine, mixing with air, and delivering the mixture to the combustion chamber?
• The device that vents excessive crankcase pressure?
• What seals the head to the cylinder to prevent leakage?
• During a leak-down test, which finding indicates head gasket failure?
• Which engine system is responsible for delivering fuel, mixing it with incoming air, and sending the resulting mixture to the combustion chamber?
• Which item is NOT typically checked during a basic engine tune-up?
• List a practical sequence for a basic engine tune-up on a typical gasoline engine.
• What term describes the ratio of the cylinder volume at bottom dead center to the volume at top dead center during the compression stroke?
• Which type of ignition system relies on an electrical spark to ignite the air-fuel mixture?
• Diesel compression ratio is measured by which property?
• How does a two-stroke engine differ from a four-stroke engine in terms of lubrication and exhaust scavenging?
• The idle speed screw sets which aspect of engine operation?
• Which engine subsystem is responsible for compressing air to increase potential energy?
• How should old fuel be disposed of and why is proper disposal important?
• What safety and environmental precautions should be followed when storing or handling fuel or working on engines?
• Cetane rating is used to measure what characteristic of diesel fuel?
• What is the purpose of a compression test?
• Short steel shaft mounted inside piston attaches piston to upper end of connecting rod.
• What is the purpose of idle speed and idle mixture screws on a typical carburetor?
• Which sign indicates a valve seating issue in the head and can cause power loss?
• What is the role of gaskets and seals in small engines, and when should they be replaced?
• A small engine may have how many cylinders according to industry usage?
• During a basic engine diagnostic, what instrument is used to verify that compression is within specification?
• In the carburetor, when the fuel level rises to the full mark, what happens?
• All parts of engine are attached/ anchored to this.
• What is the term for spontaneous ignition of the entire air-fuel charge within the cylinder?
• What is a practical step to verify there is no fuel leakage around the carburetor during startup?
• Which device maintains engine speeds under varying loads?
• Octane rating describes which property of gasoline?
• What is the function of the crankcase ventilation system and what problems can occur if it is blocked?
• What is a reed valve in a two-stroke engine, and what are common symptoms of reed valve failure?
• How can you identify a lean condition from spark plug characteristics?
• Engine efficiency is described as the conservation of fuel, time, materials and environment. Which option represents this concept?
• Which component houses the piston and contains the combustion chamber?
• What were the first automobiles called?
• Which part of an engine cylinder wears faster due to heat and combustion?
• Which type of engine burns less clean and has no camshaft, valves, or push rods?
• Why is proper air-fuel ratio critical in small engines and how is it controlled by the carburetor?
• What is the primary purpose of piston rings?
• Which test measures an engine's ability to create compression?
• What is the function of the float and needle valve in a carburetor?
• In diagrams, the part marked with E or X identifies which valve?
• Which statement best matches the typical diesel compression ratio range?
• Which of the following is one of the eight systems in a small engine that removes heat?
• What steps constitute winterizing a typical gasoline-powered small engine?
• What is the short steel shaft mounted inside the piston that attaches it to the upper end of the connecting rod?
• Which energy transformation occurs in an internal combustion engine?
• What is the purpose of the starter recoil spring and what causes it to fail?
• Gasoline compression ratio is measured by which property?
• An expanding ring placed in the grooves of the piston to seal it against the passage of fluid or gas.
• Which test is used to verify ignition condition when diagnosing a no-start condition?
• The movement of the piston from its top-most position in the cylinder to the bottom-most position in the cylinder is called ________.
• How does ethanol in gasoline affect small engines and what practices help mitigate issues?
• Which of the following is one of the eight systems in a small engine that supplies the air-fuel mixture?
• Which component is tasked with maintaining engine speed under varying loads?
• Describe the function of ignition coil/magneto and the basic principle of spark generation on small engines.
• What is the purpose of a bench-test or 'bench run' for a small engine and what steps are involved?
• What is the primary purpose of performing a compression test on a small engine?
• Engine life depends on this...
• The major rotating part of the engine. It converts the reciprocating (back-and-forth) motion of the piston into rotary (circular) motion.
• What is the function of a flywheel key in ignition timing, and what symptom indicates a sheared key?
• For small engines, gasoline should be kept in which condition?
• Which octane rating can handle the most compression before ignition?
• Which term describes how much fuel can be compressed before it spontaneously ignites?
• Which method best detects a vacuum leak in the intake system and why is it problematic?
• The piston at the top of its travel is referred to as which position?
• Which engine type is typically described as operating without forced induction?
• How do you inspect a reed valve and when should it be replaced?
• Which valve allows the air-fuel mixture into the cylinder?
• Which of the following is not a symptom of reed valve failure?
• What is the proper approach to torque spark plugs and why is it important?
• How would you test a fuel pump to confirm it is delivering fuel to the carburetor?
• During a carburetor cleaning, why is compressed air used after applying cleaner?
• Which engine component rotates once in a four-stroke cycle?
• Which fuel-handling action is recommended when storing a small engine for a long period?
• During a no-start diagnostic, which fuel-related check is essential?
• Which component's inertia keeps the crankshaft spinning and smoothes engine operation?
• Which problem can occur if spark plugs are over-tightened?
• How can you safely test for spark using a spark tester rather than just grounding the spark plug?
• In diagrams, the part marked with I or IN identifies which valve?
• In engine terminology, what does the acronym BDC stand for?
• Connects the piston to the crankshaft, held onto piston by the wrist pin.
• What is the name of the passage that vents the crankcase to relieve pressure?
• What are the four strokes of a typical four-stroke engine, in order?
• What steps would you take to diagnose an overheating condition on an air-cooled engine?
• What were early fuel sources used in engines?
• Which five items are necessary to make an engine run?
• If a carburetor floods, what are the likely causes and how would you fix it?
• Most lawn mowers require an oil change after how many hours of operation?
• What are common symptoms of a blown head gasket in a small engine?
• Small engines are typically less than _____ horsepower.
• How does air filtration affect engine performance, and what are common filter types used on small engines?
• Octane rating is used to measure what characteristic of gasoline?