Generac Power Systems GTH760, Service Manual

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0.2 volt drop. If greater, a check of each wire and terminal
connection should be made. At each connection, no more
than 0.2 volts should be seen.
5. Check the (-) negative side of the system. Place the VOM
(+) positive lead on the starter case and the other lead on
the (-) negative post of the battery. Crank the engine and
observe the reading, it should be less than .2 volts.
6. If greater than 0.2 volts, check all wire connections on the
(-) negative side of the starter. There should not be any
readings higher than 0.2 volts.
STArTer AMP drAw TeST
This test requires a special tool called a clamp-on type amp
meter. most repair shops should be able to perform this test.
1. Place the amp meter clamp on the (+) positive cable run-
ning from the battery (+) post to the starter post.
2. Ground the ignition and crank the engine (no longer than
15 seconds). The starter amp draw should be around 200
amps during cranking.
Excessive draw could be caused by the following:
• Faulty starter. To verify this, the starter should be removed
from the engine and bench checked prior to replacing. Do
an amp draw test on the bench. The starter should not
exceed 62 amps with a minimum pinion speed of 3250 rpm.
See Figure 6-5.
STAR
TER
CONTAC
TOR
STAR
TER
MOTOR
TA
CHOMETER
12
VOLT
BA
TTERY
CLAMP ON
AMP METER
VISE
Figure 6-5. Testing Starter Motor Performance
• Engine oil viscosity too heavy (see engine manufacturer’s
Operators Manual).
• Some equipment manufacturers may use a constant drive
pump, which may have too heavy of oil or too tight of belt
tension.
• Internal engine problem. Turn the engine over with a socket
and ratchet to make sure it turns over easily.
• Battery cable is loose or too small.
• Battery terminals are corroded.
bATTerY INForMATIoN
A 12 volt battery is used to operate the starter motor on
Generac OHVI V-Twin engines. For best starter life and perfor-
mance, the battery should have a rating of at least 450 cold
cranking amps at 0°F.
*
wArNING: wear eye protection when servicing the
battery. Avoid skin contact. If contact does occur,
flush with cold water and consult a physician.
*
CAuTIoN: before servicing battery, disconnect nega-
tive (-) battery cable and then disconnect the positive
(+) battery cable.
*
wArNING: batteries produce hydrogen, an explosive
gas. do not store or charge a battery near an open
flame or devices which utilize a pilot light or can
create a spark.
Figure 6-6. Typical Battery
INSTALLATION:
1. Before installing battery, connect all equipment to
be operated.
SeCTIoN 6: eleCTrIC STArTer
6-3
6