GMC 1976 ZEO 6083 Maintenance Manual page 706

Figure 42-Coil Test
CAUTION :
This engine uses a 12-volt, nega-
tive groundsystem . Alternatormust be con-
nected to battery at all times when engine is
running . Do not reverse battery cables.
BATTERY INSPECTION
Check battery cells with a hydrometer . The spe-
cific gravity reading should be approximately 1 .280
at 80°F. (figure 43).
If one or more cells are low on water, add dis-
tilled water and recharge . Follow charging proce-
Figure 43-Specific Gravity Test
ONAN MOTOR GENERATOR
24C- 2 9
dures given in "Batteries," SECTION 6Y, ENGINE
ELECTRICAL .
Keep the battery case clean and dry. An accumu-
lation of moisture will lead to a very rapid discharge
and battery failure.
Keep the battery terminals clean and tight. After
making connections, coat the terminals with a light
application of petroleum jelly or grease to retard
corrosion.
NOTE :
For complete discussion of battery ser-
vice and maintenance, refer to SECTION 6Y,
ENGINE ELECTRICAL.
FLYWHEEL ALTERNATOR
(FIGURE 44)
This unit is equipped with a permanent magnet
flywheel alternator and solid-state voltage regulator-
rectifier (output control) . As with all solid-state elec
trical units, precautions are necessary when
servicing. Observe the following :
PRECAUTIONS:
1 . Do not connect battery cables in the wrong
polarity .
2. Do not short together alternator stator leads.
3. Do not run without a battery. Damage will
occur to regulator and battery ignition coil.
PRESERVICE CHECKS :
1 . Check for a good ground between equipment
and regulator-rectifier case .
Figure 44-Flywheel Alternator System