ELECTRICAL SYSTEM
115
• Some high impedance test lights are capable of
indicating whether the current being sampled is
AC or DC.
Battery Jumper Cables
• The obvious use: jumper cables can be used to
jump-start equipment to get it into the shop. This
is not recommended for any fuel injected Kohler-
powered equipment.
• The clever use: If the technician suspects that
there is resistance on the ground side of the sys-
tem, a quick-and-dirty test can be made using
jumper cables.
• Connect one cable clamp to the negative post of
the battery, and connect the clamp at the other
end of the same cable to the engine block.
• If there is an immediate difference in starter
motor performance, use the voltage drop tech-
nique discussed later in this section to identify
the source of the resistance.
Ammeters and specialized charging system testers
• Inductive ammeters are available in many forms.
Some are as simple as a gauge to be held
against the circuit in question when it is ener-
gized. See Figure 7.33.
Figure 7.33
DMM with inductive
ammeter feature
Inductive ammeter
• There are two primary reasons to measure
amperage:
1. To check the out-put of a charging system
or battery.
2. To check the performance of a component
that draws a substantial flow of power, typ-
ically a motor or clutch.
• Briggs and Stratton sells a DC Shunt that con-
verts amperage into a reading on the millivolt
scale of a DVOM. Briggs and Stratton part #
19359 covers low amperage systems, while part
# 19468 tests higher amperage systems.
See Figure 7.34.
• Usage of the DC Shunt tool is detailed in the
1995 and 1999 editions of their Update Seminar
materials.
NOTE: The operating principle is based on
Ohm’s Law, as described earlier in this section.
Figure 7.34
To negative
battery post
Connect to
battery end of
ground cable
DVOM on
300Mv
scale
calibrated
resistance:
creates
amperage
reading
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