GMC 1976 ZEO 6083 Maintenance Manual page 679

24C- 2 ONAN MOTOR GENERATOR
Figure 2-Onan Motor Generator (Right Side View)
ONAN MOTOR GENERATOR
TROUBLE DIAGNOSIS
Figure 3-Onan Motor Generator (Left Side View)
CONTROL SYSTEM TROUBLESHOOTING GUIDE
This troubleshooting section is divided into four
IMPORTANT:
Always stop the power plant and
parts, A, B, C and D as follows:
disconnect the battery leads before removing the
cover or printed circuit board. After removing
A. Engine does not crank.
control cover, use a long nose pliers to remove
flag connectors from terminals on board. Pull
B. Engine cranks but does not start.
flag connectors straight out to avoid breaking
control board terminals . Although dust covers
C. Engine runs for 3 or 4 seconds, then stops.
on two relays (K2 and K3) are removable. DO
NOT attempt to adjust the contacts on these
relays ; they are precision set at the factory. The
D. Low battery - low charge rate.
only maintenance required on these relays is
blowing out sand and dirt with a low pressure,
compressed air source .
To correct a problem, answer the question ofthe step
either YES or NO. Then refer to the number in
whichever column question was answered, and pro-
ceed to that step next.
A. ENGINE DOES NOT CRANK
YES NO
1A .
Check battery. Are battery terminals clean and are cables tight? 2A -
2A . Check battery cables for correct polarity . Is 12 volts present across battery
terminals with engine stopped and is 8 volts or higher present with engine
cranking? 3A 10A
3A .
Remove cover on printed circuit board. Jumper terminal 7 to 3. Press start
switch . Does engine crank? 4A 5A