Service Manual
57
ELECTRIC START SYSTEM
(
12 VOLT
)
Alternator Output Testing
1. To check output of the alternator accurately, it is
necessary to run the en
g
ine at operatin
g
speed,
2900 ± 300 RPM. Readjust the
g
overnor if
necessary. Refer to pa
g
e 26 (Presettin
g
the
Governor (DuraForce En
g
ines Only).
2. With the en
g
ine runnin
g
, unplu
g
the battery
connector and reconnect the plu
g
so that only the
black wires are connected. Usin
g
a multimeter, set
to read 500 milliamps. Connect the red lead to the
red wire
g
oin
g
to the battery and the black lead to
the red wire
g
oin
g
to the mower.
CAUTION: Keep hands and feet away from the
blade.
3. Measure alternator output. The readin
g
should be
from 190-450 M.A. (Milliampere) at 2900 ± 300
RPM. If output is not within specification, check
the alternator air
g
ap.
Alternator Air Gap Adjustment
1. Rotate the flywheel until the ma
g
nets are directly
adjacent to the alternator. There should be a .010”
(.25 mm) air
g
ap.
2. If
g
ap is incorrect, loosen the alternator mountin
g
bolts sli
g
htly allowin
g
the flywheel ma
g
nets to pull
alternator a
g
ainst the
g
au
g
e. Ti
g
hten the bolts to
75 in. lbs., and recheck the air
g
ap. (See Fi
g
ure
104.)
Fi
g
ure 104
6.tif
Alternator Resistance Check
1. Disconnect the electronic cup assembly from the
wirin
g
harness. Connect one ohmmeter (RX-1
scale) lead to the
g
reen wire of the wirin
g
harness
and the other to the en
g
ine block. (See Fi
g
ure
105.)
2. Measure resistance. The resistance should be
from 2.7 to 3.3 ohms. If specification is not met,
check resistance at alternator connection. If
specification is met at the alternator, look at the
harness for breaka
g
e. If specification is not met at
alternator connection, replace the alternator.
Fi
g
ure 105
0891-004
Cup Assembly Test
1. The cup assembly consists of a capacitor and
diode. Its function is to convert alternatin
g
current
to direct current and increase the volta
g
e.
2. Disconnect the electronic cup assembly from the
wirin
g
harness. Connect one ohmmeter (RX-1
scale) lead to the
g
reen wire of the cup side of the
connector and the other lead to the red wire of the
connector.