GMC 1976 ZEO 6083 Maintenance Manual page 681

24C- 4 ONAN MOTOR GENERATOR
C . ENGINE RUNS 3 OR 4 SECONDS - THEN STOPS*
YES NO
1C .
Check oil level . Refill to FULL mark on dipstick . Does engine now continue
to run?
- 2C
2C . Check voltage from terminal 11 to 12 . Is it 12 volts with engine stopped
and does voltage drop to zero when engine runs?
- 3C
3C .
Check oil pressure sensor wire for shorts to ground by visually tracing
wire from S2 low oil pressure switch to control . Is wire grounded?
4C 5C
4C . Replace or repair wire making sure it isn't rubbing against anything
that may again cause a grounding problem .
- -
5C . Replace low oil pressure switch S2 .
- -
NOTE : Remote control leads may be shorted or grounded .
D. LOW BATTERY - LOW CHARGE RATE
YES
NO
1D . With engine cranking, measure voltage at terminal 8 to BAT terminal of
K1 start solenoid . Is 6 volts present?
2D
3D
2D . Check battery connections . They must be clean and tight .
- -
3D .
Check flywheel alternator G1 output. Disconnect AC lead that connects
to voltage regulator VR1 and connect voltmeter to this lead and BAT
terminal of K1 start solenoid . This checks AC open circuit voltage . Start
engine. Is AC output voltage approximately 28 volts with unit running at
1800 rpm?
5D 4D
4D . Replace alternator stator G1 .
- -
5D . Connect a voltmeter across battery terminals . Start engine . Does DC
voltage increase to 13 to 14-112 volts after engine is running for a few
minutes?
- 6D
6D .
Remove and replace voltage regulator VR1 .
- -