EETC Cheat Sheet 2026

The 30 highest-yield EETC facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. On a magneto-based ignition system, what component triggers spark at the correct crankshaft position? → Points or electronic trigger module aligned with the flywheel magnets
2. In a final drive that uses a planetary gear set, what is the primary purpose of this arrangement? → To provide significant torque multiplication and speed reduction.
3. Which type of cooling system uses fins on the cylinder and head to dissipate heat directly into the surrounding air? → Air cooling
4. What component in a float-type carburetor controls the fuel level in the bowl? → The needle valve and float assembly
5. What ratio of antifreeze to water is typically recommended for year-round protection in most US climates? → 50% antifreeze / 50% water
6. When diagnosing the cause of a bent crankshaft on a lawnmower, which of the following is the most common cause? → Impact with an immovable object like a rock or tree stump
7. An engine has good compression and fuel but will not start. A spark test shows a weak orange spark. What is the most likely cause? → Worn ignition coil or incorrect coil-to-flywheel air gap
8. What is the correct method for measuring spark plug gap on a small engine? → Wire-type feeler gauge inserted between center and ground electrode
9. What is the most common type of valve used in a two-stroke engine? → Reed valve
10. What physical principle draws fuel from the bowl into the airstream inside a carburetor? → The venturi effect creating low pressure at the narrowed passage
11. When performing a compression test on a four-stroke engine, which of the following steps is essential for an accurate reading? → The throttle must be held wide open.
12. In a typical two-stroke engine's port timing sequence, which port is the first to open as the piston moves downward on the power stroke? → The exhaust port
13. How does an oil cooler benefit engines in high-demand commercial equipment applications? → It removes heat from engine oil, reducing oil breakdown and extending oil life
14. Which of the following factors may affect the operating temperature of an air-cooled engine? → All of the above
15. What is the primary function of the thermostat in a small engine cooling system? → Regulate coolant flow to maintain operating temperature
16. When inspecting a used spark plug with a white or gray blistered electrode, what does this indicate? → Engine running too lean or timing too advanced causing overheating
17. What is the purpose of the resistor built into many modern spark plugs? → Suppress radio frequency interference (RFI) from the ignition system
18. When testing a common rail fuel injector, a technician performs a return flow (back-leak) test. What is the primary purpose of this test? → To identify excessive internal leakage within the injector.
19. What causes a cooling fan shroud to be critical on an air-cooled engine? → It directs airflow over all cylinder fins evenly to prevent hot spots
20. What type of coolant is recommended for aluminum engine components in modern small engines? → OAT or HOAT coolant designed for aluminum protection
21. How many camshaft revolutions are equivalent to one revolution of the crankshaft in a four-stroke engine? → Half
22. What is the correct procedure when replacing a liquid-cooled engine thermostat? → Install with the temperature-sensing end facing the engine block
23. What is the purpose of the emulsion tube found in some carburetors? → To introduce air into the fuel stream and atomize it before the venturi
24. Which carburetor circuit provides fuel to the engine during idle operation? → Idle circuit
25. What is the air gap specification between the ignition coil armature and flywheel magnets used for? → Setting the magnetic coupling distance for proper coil charging and spark energy
26. Which of the following is a critical first step when diagnosing a 'crank, no start' condition on a modern compact diesel engine? → Checking for diagnostic trouble codes (DTCs) with a scan tool.
27. When testing the AC voltage output from a stator on a small engine, where should the multimeter leads be placed? → Across the two stator output wires (or pins) coming from under the flywheel housing.
28. What is used to ignite the air/fuel mixture inside the cylinder in a four-stroke engine? → A spark plug
29. What color exhaust smoke on a four-stroke engine indicates a rich fuel mixture condition? → Black smoke indicating unburned fuel
30. What does a black, sooty spark plug indicate about engine combustion? → Rich fuel mixture or oil fouling