Yanmar 3YM30, Service Manual

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3. Troubleshooting
59
3.3 Troubleshooting (Concerning engine and fuel injection
equipment)
Malfunctions Causes Remedies
The engine does not operate
1. Fuel oil is not injected from the
injection pump
1. There is no fuel oil in the fuel
tank
2. The fuel line from the fuel tank
is blocked
3. The fuel is clogged
4. There is air in the fuel filter or
the pump chamber
5. The accelerator linkage is not
properly connected
6. The magnet valve wiring is
broken or its armature is
sticking
7. The feed pump blades are
sticking, and therefore not
operating
8. The drive gear or woodruff key
is broken
Supply fuel and bleed the system
Clean or replace
Clean or replace
Bleed the system
Repair
Repair or replace
Repair or replace
Replace
2. Injection timing is incorrect 1. The drive gear or belt
connections are incorrect
2. The injection pump is
incorrectly installed on the
engine
3. The roller holder assembly’s
roller or pin is worn excessively
4. The plunger is worn excessively
Repair
Repair and adjust injection timing
Replace the assembly
Replace the distributor assembly
3. The nozzle does not operate 1. The nozzle or nozzle holder is
functioning incorrectly
Inspect, then repair or replace
4. The engine operates but only
for short time
1. The pipe(s) to the injection
pump is blocked or the fuel filter
is clogged
2. The fuel oil contains air or water
3. The feed pump’s delivery
quantity (or pressure) is
insufficient
Clean or replace the pipe(s) or fuel
filter
Bleed of air or replace the fuel oil
Repair or replace
5. The engine “knocks” 1. The injection timing is too
advanced
2. The nozzle or nozzle holder is
functioning incorrectly
Readjust the timing
Inspect, then repair or replace