Hobart 6921 Series Operation And Maintenance Manual page 105

OM-2040 / Operation and Maintenance Manual
90D20 / Generator Sets
Engine and Controls (cont).
Trouble, Symptom & Condition
Engine will not start. Cranking
speed normal. (cont.)
4. Engine starts. Stops after a
few seconds by automatic
shut-down.
5. Engine runs at idle speed.
Engine "ON" indicating light
(27, Fig. 1) does not glow.
February 28/94 Revised
Test or Inspection
f. Improper valve clearance
adjustment.
g. Blower not functioning.
a. The shut-down circuit may
have functioned normally to
stop the engine because of
low lubricating oil pressure.
b. Defective low oil pressure
switch (1, Fig. 4).
c. Defective or incorrectly
wired high temperature
switch (2, Fig. 4)
a. Lamp defective.
b. Indicating light body poorly
grounded.
c. Defective fuel pressure
switch (5, Fig. 4).
Corrective Action
Check and adjust valve
clearance in accordance with
instructions in Detriot Diesel
Operator's Manual.
Inspect blower drive shaft and
drive coupling. Replace parts as
required.
Reset shut-down valve latch (7,
Fig. 3). Start the engine and
observe oil pressure gage. if
pressure is less than 12 PSI,
stop engine at once and check
for cause of low pressure.
Repair as required..
Reset shut-down valve latch (7,
Fig. 3). Disconnect ORANGE
wire at low oil pressure switch.
Start engine. Observe oil
pressure. If pressure is 38 PSI,
or more, check voltage from oil
pressure switch terminal (one
which had ORANGE wire
removed) to ground. If
approximately 12-V DC is
indicated, the oil pressure
switch is defective. Stop engine
and replace switch (1, Fig. 4).
Check wiring to high
temperature switch. Two
yellow-blue wires should be
connected to N.O. terminal.
Yellow wire should be
connected to C terminal. Check
resistance between terminals N.
O. and C with wires removed.
Infinite resistance indicates a
good temperature switch. A
readable resistance indicates a
defective switch. Replace
switch.
Replace lamp.
Be sure light is grounded
properly.
Check switch. Replace if
defective.
Chapter 3-1
Page 13