Identification Of Tecumseh Ignition Systems - Tecumseh ECV100-120 - TECHNICIAN S Handbook

IDENTIFICATION OF TECUMSEH IGNITION SYSTEMS

COMPONENTS OF A TECUMSEH MAGNETO
IGNITION SYSTEM (DIAG. 7)
A. Flywheel with magnets
B. Coil
C. Condenser
D. Spark plug
E. Contact points
F. Ignition cam
G. Stator plate (dust cover, cam wiper, and laminations.)
H. Flywheel key
The flywheel with magnets provide the magnetic flux
(or field) which is necessary to induce the low voltage in
the primary circuit. A horseshoe magnet is a good
example of how the magnets function in the flywheel. The
magnets are either cast in or glued onto the flywheel,
and are not a replaceable item (diag. 8).
The ignition coil is used to increase the low voltage in
the primary to high voltage in the secondary, capable of
jumping the spark plug gap. The coil consists of a primary
and a secondary winding of wire. The primary is the low
voltage (200 - 300 volts) winding, consisting of
approximately 150 turns of heavy gauge wire next to the
core. The secondary winding consists of approximately
10,000 turns of very fine wire wrapped over the primary.
When induced by the primary, the secondary winding
generates a voltage of between 10,000 - 20,000 volts,
which can arc the spark plug gap (diag. 9).
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