1. Chapter 9
Ignition Systems
page 147

2. Basic Ignition System Operation
charge builds up in coil (12 volts in)
creates a magnetic field (windings of wire)
voltage is stepped up (secondary windings)
switch open (magnetic field collapses)
high voltage discharged (to plug)

3. Fundamental Electrical Principles
Electricity is lazy
Electricity wants to go to ground
electron theory (-) to (+)
conventional theory (+) to (-)
Conductors
Insulators

4. The Electron Theory
Electricity moves from – to +

5. Electrical Units of Measurement
Volts---- Push V
Current ---Quantity A
Resistance ----Resistance to flow 

6. Ohm’s Law
E = I x R
E / I = R
E / R = I E I R

7. Magnetism Alike charges repel (-) (-)
Dissimilar charges attract (-) (+)

8. Magnets & Electricity Magnets can be used to for electricity
Electricity can be used to form magnets
Electricity when applied to magnets make stronger magnets

9. Ignition Coils Coils of wire wrapped around an iron core
Step up transformer

10. Spark Plugs
Spark plugs contain an air gap for electricity to create a spark and make a seal

11. Heat Ranges
The difference between a "hot" and a "cold" spark plug is in the shape of the ceramic tip.
The manufacturers will select the right-temperature plug for each engine.
Some engines with high-performance naturally generate more heat, so they need colder plugs.
If the spark plug gets too hot, it could ignite the fuel before the spark fires
It is important to stick with the right type of plug
Engine that burn oil may need hot plugs

12. Measuring Spark Plug Temperature

13. Types of Electrodes
Center electrode
Side electrode

14. Switching Devices
Breaker points
Electronic

15. Breaker Points
Ran by cam shaft

16. Electronic Switching Devices
NO breaker points to burn or wear out

17. The MBI Magneto System Mechanical Breaker Point Ignition
produce power without an outside power source
Condenser-prevents arching

18. The MBI Magneto Cycle
Magnets pass legs

19. Coil
150 turns of large wire
20,000 turns of fine wire
Iron core

20. The Stop Switch Plug only fires when points open Switch grounds points
Fasten metal to head bold

21. Ignition Advance Systems
Cause spark earlier
BTDC
As engine warms up
Speeds up
Centrifugal
Vacuum
Mechanical

22. Dwell & Cam Angles
Time points stay closed
Lobes size = dwell time

23. Electronic Ignition Solid state No maintenance No points-burning
Spark plug life
Easy starting
Higher output
Starts flooded engine
Higher spark output

24. Electronic Ignition Hermetically sealed Uniform performance
Good under adversity
Improved idling
Smoother power under load

25. Operation of Capacitive Discharge Ignition ( CDI)
Solid State
Newest
NO Breaker points
Magnets only moving parts

26. Operation of Transistor Controlled Ignition (TCI) Systems

27. Magneto Ignition Systems Compared

28. Battery Ignition Systems
Low voltage primary circuit
High voltage secondary circuit
ignition switch
builds field
field collapses
spark to plug

29. High Voltage Secondary Circuits
Uses a step up transformer
Several winding of wire / iron core

30. Auto-Transformer Type Ignition Coils

31. The Lead Acid Battery

32. Vehicle batteries