Electrical Terms; Basic Checks - Tecumseh V-twin Technician's Handbook

1. The starter circuit wiring requires a rating of #6 or
lower gauge number.
2. The charging circuit wiring requires a #16 or lower
gauge number. (20 amp systems requires #14 or
lower gauge number).
3. The magneto circuit wiring (ground circuit) requires
#18 or lower gauge number.
Tecumseh Products Company's standard wiring color
codes effective August, 1992 are as follows:
Code Product
Yellow - Alternator A.C. Leads
Red - Alternator D.C. + Leads
Brown - Alternator D.C. - Leads
Black - Alternator Ground Leads, Battery
Ground Leads
Orange - 12 Volt Starter B + Leads
Dark Green - Ignition Shut-Off Leads
NOTE: Prior to August 1992, wire codes changed
according to model and specification numbers.

ELECTRICAL TERMS

ALTERNATOR - An alternator consists of coils of wire
wound around a metal lamination stack. When a magnet
is moved past the coils, a current is induced in the coils.
In general, the greater the number of coils and magnets
in the flywheel, the greater the output of the alternator.
RECTIFIERS and DIODES - Charging a battery requires
the A.C. (alternating current) produced by the alternator
be changed to D.C. (direct current). This is accomplished
by using a diode or rectifier.
REGULATOR/RECTIFIERS - This combines a regulator
with a rectifier. The regulator controls the amount of
current flowing to the battery based on the electrical
system need. The rectifier changes the alternating current
to direct current.
CONDUCTORS - A conductor is a material that allows
an electric current to pass through it. All metals are
conductors of electricity, but some are better conductors
than others. Silver, copper and gold are some of the
better known conductors.
INSULATORS - An insulator is a material that will not
allow an electric current to pass through it. Some of the
more common materials that are insulators are glass,
plastic, rubber, ceramics and porcelain.

BASIC CHECKS

Before going into extensive diagnostics, be sure to
perform the more basic checks first, such as:
1. Battery not fully charged or defective.
2. Terminals or connections that are loose or corroded.
3. Cracked insulation or broken wires grounding out.
4. Improper wire connections.
5. Defective ignition switch.
6. Properly functioning Operator Presence System.
(Safety Interlocks)*
7. Proper valve lash affecting compression relief.
*NOTE: All lawn and garden tractors built after July of
1987 are required to have an operator presence system.
Many came equipped with such a system prior to this
date. If the tractor is "cutting out" or will not start, these
switches are a PRIMARY area to check.
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