GMC 4000 Series Service Manual page 314

SYMPTOM A - LOW STARTING RPM
POSSIBLE CAUSES
1. Improper oil viscosity.
2. Low battery output.
3. Low temperature.
4. Defective starter or solenoid.
SYMPTOM B - LOW CYLINDER COMPRESSION
POSSIBLE CAUSES
1. Burned or warped valves.
2. Improper valve lash.
3. Worn or broken piston rings.
4. Defective cylinder head gasket.
SYMPTOM C - LACK OF FUEL
POSSIBLE CAUSES
1. Fuel line shut-off valve closed.
2. Engine stop mechanism not released.
3. Accelerator linkage not operating properly.
4. Low fuel supply.
5. Clogged vent in fuel tank cap.
6. Break in fuel supply line allowing air to be
drawn into system .
7. Clogged fuel filters.
8. Air trapped in system .
9. Water or ice in fuel system .
10. Defective fuel supply pump.
11. Overflow valve leaking or stuck open.
12. Low fuel delivery.
G M C S E R V I C E M A N U A L
jbiaoHaild. Chant
HARD STARTING
1. Drain crankcase and refill with recommended
2. Check for:
3. Use a starting aid.
4. Replace defective parts.
1. Overhaul cylinder head.
2. Adjust to proper clearance.
3. Overhaul engine.
4. Replace gasket.
1. Open shut-off valve.
2. Check and as necessary, correct operation of
3. Check linkage operation and adjust or repair
4. Check amount of fuel in tank, fill if supply is
5. Clean or replace cap.
6. Replace or repair lines.
7. Service filters.
8. Bleed air from system .
9. Thaw if frozen, and drain water out of tank and
10. Make pressure test at secondary filter.
11. Clean and inspect overflow valve.
12. Check excess fuel starting device to determine
TORO-FLOW DIESEL ENGINE
REMEDY
grade of oil (Refer to LUBRICATION (SEC. 0)
in this manual for Viscosity vs Temperature
Chart). Also change oil at recommended inter­
vals.
a. Undercharged or defective battery. Replace
battery if necessary.
b. High resistance in starting circuit. Clean
and/or tighten all connections.
REMEDY
REMEDY
mechanism. Stop button must be pushed incom ­
pletely.
as required.
low.
filters.
if sticking.___________________________________
Sec. 6B
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