EETC - Equipment & Engine Training Council Ignition Systems and Spark Technology Questions and Answers Flashcards

What is the difference between a capacitor discharge ignition (CDI) system and a battery-powered inductive ignition system?

Answer: CDI uses stored capacitor energy discharged through the coil; inductive systems charge the coil directly from battery current

CDI stores energy in a capacitor and releases it rapidly through the coil for a fast high-voltage spike, while inductive systems build energy slowly in the coil's magnetic field before collapsing it.

How does a technician correctly set the ignition coil air gap on a small engine?

Answer: Use a wire feeler gauge between the coil armature legs and flywheel magnets while magnets are aligned

With the flywheel magnets aligned under the coil armature legs, a feeler gauge of the specified thickness is placed between them and the coil is tightened so it lightly grips the gauge.

What electrical test can confirm a faulty ignition coil on a small engine without a spark tester?

Answer: Measure coil primary and secondary winding resistance with an ohmmeter and compare to specifications

Measuring primary and secondary winding resistance with an ohmmeter and comparing values to the manufacturer's specifications can identify open or shorted coil windings.

What is pre-ignition in a small engine and what typically causes it?

Answer: Combustion occurring before the spark fires, caused by hot spots like carbon deposits or an overheated plug tip

Pre-ignition occurs when the air-fuel mixture ignites from a hot spot (such as a carbon deposit or overheated plug tip) before the spark plug fires, causing damaging uncontrolled combustion.

On equipment with an electronic ignition module, what common failure symptom occurs when the module overheats?

Answer: Engine runs fine when cold but dies after reaching operating temperature and restarts after cooling down

A failing electronic ignition module often breaks down electrically when hot, causing the engine to run normally when cold, die after warming up, and restart only after the module cools.

Why is it important to use the spark plug type and heat range specified by the engine manufacturer?

Answer: Using the wrong heat range can cause fouling, pre-ignition, or engine damage

The manufacturer's specified plug heat range is matched to the engine's combustion temperature profile; a wrong heat range causes either fouling from a too-cold plug or pre-ignition from a too-hot plug.