• 50 questions

NOCTI Small Engine Technology Practice Test

Unofficial practice for NOCTI Small Engine Technology: safety, maintenance, lubrication, fuel, governor, ignition, valves, assembly and troubleshooting.

A shop buys a carburetor kit for $12.00 and marks parts up 40% over cost. What price goes on the invoice?

Pick an answer, then press Check answer. Then you see Correct or Not quite, with the reason. Keys: A to D pick, Enter checks.

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Exam mode: 50 questions, 48 minutes.

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Unofficial practice questions, not affiliated with NOCTI. Bank checked October 16, 2026.

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All 50 questions

Safety 5

  • A technician tests the blade control of a walk-behind rotary mower. Under the federal safety standard, within how many seconds of release must the blade come to a complete stop? Safety Standard for Walk-Behind Power Lawn Mowers, 16 CFR 1205.5, paragraph (a)(1). Written to NOCTI Small Engine Technology (4178), Safety
  • An engine must be test-run after a repair. Why does OSHA warn against running a gasoline engine in an enclosed space? OSHA Fact Sheet, Carbon Monoxide Poisoning. Written to NOCTI Small Engine Technology (4178), Safety
  • Carburetor cleaner is spilled across the shop floor. Which section of its safety data sheet gives the methods for containing and cleaning up the spill? OSHA, 29 CFR 1910.1200, Appendix D, Safety Data Sheets (Mandatory), item 6. Written to NOCTI Small Engine Technology (4178), Safety
  • Gasoline for the shop is kept in an approved safety can. By the OSHA definition, what is the largest capacity a safety can may have? OSHA, 29 CFR 1910.106, paragraph (a)(29). Written to NOCTI Small Engine Technology (4178), Safety
  • The shutoff device on a power lawn mower has stopped the engine. Under the OSHA rule for power lawnmowers, what must the device require before the engine can run again? OSHA, 29 CFR 1910.243, paragraph (e)(1)(iii). Written to NOCTI Small Engine Technology (4178), Safety
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General Shop Practices 4

  • A job ticket shows that work on a tiller began at 9:40 and ended at 11:10. How much labor time goes on the ticket? Written to the NOCTI Job Ready Credential Blueprint for Small Engine Technology (4178), General Shop Practices; the answer is arithmetic on the numbers in the question, worked twice
  • A shop buys a carburetor kit for $12.00 and marks parts up 40% over cost. What price goes on the invoice? Written to the NOCTI Job Ready Credential Blueprint for Small Engine Technology (4178), General Shop Practices; the answer is arithmetic on the numbers in the question, worked twice
  • A work sheet for a tune-up lists three spark plugs at $4.25 each and two quarts of oil at $6.50 each. What is the parts total before tax? Written to the NOCTI Job Ready Credential Blueprint for Small Engine Technology (4178), General Shop Practices; the answer is arithmetic on the numbers in the question, worked twice
  • An invoice lists $40.00 in parts and 1.5 hours of labor at $70.00 an hour. A 5% sales tax applies to the whole bill. What is the total? Written to the NOCTI Job Ready Credential Blueprint for Small Engine Technology (4178), General Shop Practices; the answer is arithmetic on the numbers in the question, worked twice

Maintenance 6

  • A mower deck is driven by a V-belt. What does the V shape of the belt do in the pulley? Wikipedia, Belt (mechanical), V belts. Written to NOCTI Small Engine Technology (4178), Maintenance
  • A screen in the muffler outlet of a string trimmer is cleaned during exhaust service. The screen is a spark arrester. What does a spark arrester do? Wikipedia, Spark arrestor. Written to NOCTI Small Engine Technology (4178), Maintenance
  • The bail lever on a mower handle must be held down for the machine to run, and the machine stops when the operator lets go. What kind of control is this? Wikipedia, Dead man's switch. Written to NOCTI Small Engine Technology (4178), Maintenance
  • The chain of a chain saw stands still at idle and begins to move as the engine speeds up. Which drive part works this way? Wikipedia, Centrifugal clutch. Written to NOCTI Small Engine Technology (4178), Maintenance
  • During service a technician clears packed grass from between the fins on a mower engine cylinder. What are the fins for? Wikipedia, Air-cooled engine. Written to NOCTI Small Engine Technology (4178), Maintenance
  • Which carburetor adjustment holds the throttle valve slightly open so that the engine keeps running at idle? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 4-13. Written to NOCTI Small Engine Technology (4178), Maintenance

Lubrication Systems 3

  • A service chart calls for 10W-30 oil. What does that multiweight rating mean? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraphs 8-6 and 8-7. Written to NOCTI Small Engine Technology (4178), Lubrication Systems
  • Many small four-stroke engines have no oil pump. In a splash lubrication system, what throws the oil onto the moving parts? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 8-17. Written to NOCTI Small Engine Technology (4178), Lubrication Systems
  • Why is oil mixed into the gasoline of a two-stroke trimmer engine? Wikipedia, Two-stroke oil. Written to NOCTI Small Engine Technology (4178), Lubrication Systems

Fuel System Fundamentals 7

  • A carburetor breaks gasoline up into tiny droplets before it reaches the cylinder. Why does this atomization matter? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 4-9. Written to NOCTI Small Engine Technology (4178), Fuel System Fundamentals
  • A chain saw must run on its side and upside down. Why does its carburetor use a diaphragm chamber in place of a float chamber? Wikipedia, Carburetor, Diaphragm chamber. Written to NOCTI Small Engine Technology (4178), Fuel System Fundamentals
  • A customer asks whether E15, gasoline with 15% ethanol, may be used in a lawn mower. What does the EPA say? U.S. EPA, E15 Fuel Registration. Written to NOCTI Small Engine Technology (4178), Fuel System Fundamentals
  • An engine is run with its air filter left off. According to TM 9-8000, what does the dirt that enters the intake do? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 4-6. Written to NOCTI Small Engine Technology (4178), Fuel System Fundamentals
  • The float in a carburetor bowl is set too high. What does the engine get? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 4-14. Written to NOCTI Small Engine Technology (4178), Fuel System Fundamentals
  • What does the choke do for a cold engine? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 4-19. Written to NOCTI Small Engine Technology (4178), Fuel System Fundamentals
  • What is the primary difference between fuel injection and carburetion? Wikipedia, Fuel injection. Written to NOCTI Small Engine Technology (4178), Fuel System Fundamentals

Governor 2

  • In a centrifugal governor, what do the weighted arms do as engine speed rises? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 4-33. Written to NOCTI Small Engine Technology (4178), Governor
  • What is the governor on most small engines for? Wikipedia, Small engine, Governor. Written to NOCTI Small Engine Technology (4178), Governor

Ignition 3

  • A push mower with a pull-cord starter has no battery. What do such engines use to fire the spark plug? Wikipedia, Small engine, Electrical system. Written to NOCTI Small Engine Technology (4178), Ignition
  • Battery ignition and magneto ignition share one fundamental job. What is it? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 15-1. Written to NOCTI Small Engine Technology (4178), Ignition
  • What makes one spark plug run hotter than another? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 15-3. Written to NOCTI Small Engine Technology (4178), Ignition

Starters and Charging Systems 3

  • A charger is connected to the battery of a riding mower. How must its wires be connected? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 12-5. Written to NOCTI Small Engine Technology (4178), Starters and Charging Systems
  • The rope of a recoil starter is pulled and let go. What rewinds the rope for the next pull? Wikipedia, Recoil start. Written to NOCTI Small Engine Technology (4178), Starters and Charging Systems
  • Shop wall outlets supply alternating current. What kind of current must reach a storage battery to charge it? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 12-5. Written to NOCTI Small Engine Technology (4178), Starters and Charging Systems

Cylinder Head and Valve, Service and Maintenance 5

  • A cylinder holds 12 cubic inches with the piston at bottom dead center and 2 cubic inches with it at top dead center. What is the compression ratio? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 2-24. Written to NOCTI Small Engine Technology (4178), Cylinder Head and Valve, Service and Maintenance; the arithmetic was worked twice
  • A valve seat is cut with a tool that is piloted in the valve guide. Why must the seat be concentric with the guide? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 3-12. Written to NOCTI Small Engine Technology (4178), Cylinder Head and Valve, Service and Maintenance
  • How does a leak-down tester check the condition of a cylinder? Wikipedia, Leak-down tester. Written to NOCTI Small Engine Technology (4178), Cylinder Head and Valve, Service and Maintenance
  • What is the purpose of the head gasket? Wikipedia, Head gasket. Written to NOCTI Small Engine Technology (4178), Cylinder Head and Valve, Service and Maintenance
  • Which two angles are commonly used when a valve seat is machined? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 3-12. Written to NOCTI Small Engine Technology (4178), Cylinder Head and Valve, Service and Maintenance

Engine Assembly 4

  • A crankcase cover is refitted with a new gasket. What does a gasket do between two mating surfaces? Wikipedia, Gasket. Written to NOCTI Small Engine Technology (4178), Engine Assembly
  • A new piston ring is checked before it goes on the piston. Why is a piston ring made with a split in it? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 3-6. Written to NOCTI Small Engine Technology (4178), Engine Assembly
  • A single-cylinder engine gets only one power stroke in two crankshaft revolutions. Which part carries it smoothly through the other strokes? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 2-10. Written to NOCTI Small Engine Technology (4178), Engine Assembly
  • The crankshaft gear and the camshaft gear each carry a small mark. What are these timing marks for? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 2-9. Written to NOCTI Small Engine Technology (4178), Engine Assembly

Troubleshooting 8

  • A four-stroke engine gives off blue smoke from the exhaust. What does blue smoke suggest? Wikipedia, Head gasket, Gasket failure. Written to NOCTI Small Engine Technology (4178), Troubleshooting
  • A mower battery sat all winter and will no longer hold a charge. What does regular charging of a stored starting battery prevent? Wikipedia, Lead–acid battery, Starting batteries. Written to NOCTI Small Engine Technology (4178), Troubleshooting
  • A mower was stored tipped over, and liquid filled the cylinder above the piston. Now the engine will not turn through a full revolution. What is this condition called? Wikipedia, Hydrolock. Written to NOCTI Small Engine Technology (4178), Troubleshooting
  • A spark plug comes out of a hard-starting engine with a heavy coating of carbon. What does this say about the plug? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 15-3. Written to NOCTI Small Engine Technology (4178), Troubleshooting
  • A warm engine runs roughly and smokes, and the choke plate is found stuck closed. What is wrong with the mixture? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 4-19. Written to NOCTI Small Engine Technology (4178), Troubleshooting
  • An engine is low on power, and gases puff from the crankcase breather. Combustion gases are leaking past worn piston rings. What is this leakage called? US Army TM 9-8000, Principles of Automotive Vehicles (1985), paragraph 3-6. Written to NOCTI Small Engine Technology (4178), Troubleshooting
  • During a leak-down test, a hissing noise comes from the exhaust pipe. What does that point to? Wikipedia, Leak-down tester. Written to NOCTI Small Engine Technology (4178), Troubleshooting
  • On a hot day an engine loses power and stalls, and it is hard to restart until it cools. Fuel has turned to vapor in the fuel line. What is this problem called? Wikipedia, Vapor lock. Written to NOCTI Small Engine Technology (4178), Troubleshooting

How this list was compiled: Our own questions, written to the competency list of the Job Ready Credential Blueprint for Small Engine Technology (code 4178, version 01, copyright 2023) that NOCTI publishes at https://www.nocti.org/wp-content/uploads/Blueprints/JRSmallEngTech4178.pdf , read 2026-10-16: a written assessment of 186 questions in 3 hours over eleven areas (Safety 10%; General Shop Practices 7%; Maintenance 12%; Lubrication Systems 6%; Fuel System Fundamentals 14%; Governor 5%; Ignition 6%; Starters and Charging Systems 6%; Cylinder Head and Valve, Service and Maintenance 10%; Engine Assembly 9%; Troubleshooting 15%), plus a performance assessment of seven jobs. This bank holds 50 in those proportions. Every rule and definition was read on 2026-10-16 in the public text named under its question: US Army TM 9-8000, Principles of Automotive Vehicles (1985, the copy at archive.org), OSHA standards in 29 CFR 1910 and an OSHA fact sheet on osha.gov, the federal safety standard for walk-behind power lawn mowers (16 CFR 1205) on ecfr.gov, the EPA page on E15 fuel, and Wikipedia. Every price, time and volume in a sum is made up for the drill, and each computed answer is arithmetic that was worked twice. Licence: Questions, choices and explanations are original work of this site. TM 9-8000 is a work of the United States Army approved for public release, and no question or example is copied from it.

How it works

Fifty questions of our own for the NOCTI Small Engine Technology test, weighted like the eleven areas of Job Ready blueprint 4178. It is unofficial, and this site has no affiliation with NOCTI, which neither endorses nor sponsors it.

Read the full guide

Eleven areas, Troubleshooting first

Troubleshooting is 15% of the written assessment and Fuel System Fundamentals 14%. Maintenance is 12%, Safety and Cylinder Head and Valve 10% each, Engine Assembly 9%, General Shop Practices 7%, Lubrication, Ignition and Starters and Charging 6% each, and Governor 5%.

48 minutes for 50

A timed round holds you to 48 minutes for the 50 questions, the speed that 186 questions in 3 hours asks for. Blueprint 4178 gives no passing score, so the round ends with a count of right answers.

Done at the bench

Seven jobs with tools in hand make up the performance half, and a quiz cannot stand in for them: starting and adjusting an engine, ignition service, measuring parts, valve service, carburetor service, invoicing parts and manual starter service.

  • Compression ratio: the cylinder volume at bottom dead center divided by the volume at top dead center.
  • A float set too high gives a rich mixture. A float set too low gives a lean one.
  • Markup is a percent of cost: a $20.00 part marked up 25% sells for $25.00.

Questions and answers

How many questions are on the NOCTI Small Engine Technology test?

The written part is 186 questions with 3 hours allowed, and a school may give it in up to three sessions. The seven hands-on jobs have a further 3 hours and 10 minutes.

What does the NOCTI Small Engine Technology test cover?

Safety devices and shop safety; invoices and job tickets; maintenance; lubrication; carburetors, fuel injection and air filters; governors; ignition; starters, charging and batteries; compression, valves and cylinder heads; timing, pistons, rings and bearings; and troubleshooting, the largest area.

Can I use this for the NOCTI Teacher test in small engines?

Mostly. Teacher assessment 5477 covers the same eleven areas in 181 questions and 3 hours, with four weights one point apart: Maintenance 13%, Lubrication 5%, Governor 6% and Ignition 5%. It is taken at an Area Test Center that NOCTI approves.

Where do I get the Small Engine Technology blueprint?

NOCTI posts blueprint 4178 as a free PDF at nocti.org/credentials/blueprints. It lists every competency, the eleven weights, ten sample questions and a sample carburetor job; this page copies none of them.

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