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

What is the primary function of the ignition coil in a small engine?

Answer: Step up low battery voltage to high voltage needed to fire the spark plug

The ignition coil transforms low primary voltage into the high-voltage spark (typically 20,000–40,000 volts) needed to jump the spark plug gap and ignite the air-fuel mixture.

On a magneto-based ignition system, what component triggers spark at the correct crankshaft position?

Answer: Points or electronic trigger module aligned with the flywheel magnets

Breaker points or an electronic trigger module detect the passing of flywheel magnets and signal the coil to collapse its magnetic field and fire the spark plug.

What is the correct method for measuring spark plug gap on a small engine?

Answer: Wire-type feeler gauge inserted between center and ground electrode

A wire-type feeler gauge provides an accurate measurement of the spark plug gap because the rounded wire matches the curved electrode shape better than a flat gauge.

What does a black, sooty spark plug indicate about engine combustion?

Answer: Rich fuel mixture or oil fouling

Black, sooty deposits on a spark plug indicate excess unburned carbon from a rich fuel mixture or oil entering the combustion chamber.

What is ignition timing advance, and why is it necessary?

Answer: Firing the spark plug before top dead center to allow full combustion pressure at the power stroke

Spark is fired before TDC so the combustion event reaches peak pressure just after TDC, maximizing the force applied to the piston during the power stroke.

What is the air gap specification between the ignition coil armature and flywheel magnets used for?

Answer: Setting the magnetic coupling distance for proper coil charging and spark energy

The air gap between the coil armature and flywheel magnets controls how strongly the magnets induce current in the coil, directly affecting spark energy output.