Petrol Engine Starting and Ignition

Question 1

What does a yellow starter warming lamp signify

Answer 1

If light remains on for 30 seconds engine must be shut down as starter motor drive as not disengaged.

Question 2

What is a magneto

Answer 2

Provides high voltage current to the spark plugs. Works on principle that current will be forced to flow in a coil of wire when it is passed between the poles of a magnet. Controlled by ignition switch.

Question 3

What is the purpose of a contact breaker

Answer 3

Powered by shaft driven by engine.
Primary winding circuit is continuously broken and remade. 2 effects.
Converts continues flow of alternating into a series of pulses. Collapse of magnetic field around primary winding produces a surge of energy in secondary winding.

Question 4

What are HT cables

Answer 4

High tension cables. High voltage low current pulses of electricity that feeds into the spark plugs.

Question 5

What is the purpose of a capacitor

Answer 5

Prevents arcing. Arcing damages breaker points. Also helps to ensure highest possible voltage induced in secondary circuit.

Question 6

What is the distributor

Answer 6

Distributes the electrical pulses to each spark plug in the appropriate sequence.

Question 7

Magneto Checks

Answer 7

Two elements Mag drop check (checking for slight drop in RPM)
Dead cut check.
If magneto fails in flight none of the cylinders will stop firing.