Yanmar 4JH4E - Troubleshooting (Concerning Engine and Fuel Injection Equipment)

3. Troubleshooting
117
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.