1. Mechanical Breacker Point (MBI) Igniton System Now its time to explore the beginning of starting your engine, the Ignition System By: Stephen

2. To learn more click on one of the following Condenser Breaker points The Flywheel Laminated coil, and legs the stop switch How it all happens

3. The Flywheel • The Flywheel is a heavy wheel which contains permanent magnets. Made of Alnico (aluminum, nickel, cobalt alloy) or of a newer ceramic magnetic material. • The flywheel is attached to the cam shaft which rotates it over the legs of the core, creating a magnetic field. Flywheel

4. Laminated coil, and legs • Primary coil contains low voltage current. • The secondary coil contains high voltage current, used to arc across the spark plug. • Legs- Current is passed through the legs and reversed to produce Primary coil current. Primary and secondary coil Legs

5. Breaker points • Breaker points are two separable points that interrupt primary circuit in a distributor or magneto for the purpose of inducing a high tension current in the ignition system. Breaker points are usually faced with silver, platinum, or tungsten

6. Condenser • The condenser is one of the most important parts of the ignition system. The condenser absorbs current the very instant that the breaker points begin to open, to prevent the breaker points from arcing and burning them out. If this were to happen then there would not be enough current in the secondary coil to arc across the spark plug

7. How it all happens, the cycle • The whole cycle begins when the flywheel turns and the magnets pass by the legs creating a flow of current through the legs. The flywheel continues to turn and the north and south pole pass over the center and side legs reversing the current direction, to induce a low current in the primary circuit through the breaker points. The current in the primary winding of the coil produce its own magnetic field, which helps to reinforce and maintain the direction of the lines of force in the center leg. It continues this until the magnetic poles in the fly wheel pass by the legs again changing the direction, but just prior to this the breaker points are opened. At this point the primary circuit collapses into the secondary windings, the condenser make helps make this happen in and instant

8. Cycle continued • At this point the primary circuit collapses into the secondary windings, the condenser make helps make this happen in an instant by absorbing the surge of the primary current to prevent and arc across the breaker points, which would mean burning them out. As this happens high voltage is induced into the secondary windings. At which time the condenser surges back to the primary windings to reverse the direction and helps increase the voltage in the secondary winding, causing secondary current to arc across the spark plug gap.

9. the stop switch • A spark plug may only fire if the points open, a stop switch like this would ground the breaker points so they wouldn’t open causing the engine to stop running. • Another way of stopping a single cylinder engine would be to have a strip of metal fastened to a head bolt. The strip would be suspended while running, then pressed against the plug wire, which would route the current the head, and prevent a spark at the spark plug.