Yanmar 4LHA-HTP Operation Manual page 412

Chapter 3 Fuel Injection Equipment
IL Troubleshooting
11. Troubleshooting
Malfunctions
The engine does
not operate
1. Fuel oil is not
injected from
the injection
pump
2. Injection timing
is incorrect
3. The roller holder assembly's roller
4. The plunger is worn excessively
3. The nozzle does
not operate
The engine
operates, but
only for a short
2. The fuel oil contains air or water
time
3. The feed pump's delivery
1. The injection timing is too
The engine
"knocks"
2. The nozzle or nozzle holder is
Causes
1. There is no fuel oil in the fuel
tank
2. The fuel line from the fuel tank is
blocked
3. The fuel filter 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
1. The drive gear or belt
connections are incorrect
2. The injection pump is incorrectly
installed on the engine
or pin is worn excessively
1. The nozzle or nozzle holder is
functioning incorrectly
1. The pipe(s) to the injection pump
is blocked, or the fuel filter is
clogged
quantity (or pressure) is
insufficient
advanced
functioning incorrectly
Remedies
Supply fuel and bleed the system
Clean or replace
Clean or replace
Bleed the system
Repair .
Repair or replace
Repair or replace
Replace
Repair
Repair and adjust injection timing
Replace the assembly
Replace the distributor assembly
Inspect, then repair or replace
Clean or replace the pipe(s) or
fuel filter
Bleed of air or replace the fuel oil
Repair or replace
Readjust the timing
Inspect, then repair or replace
3-1-55
, 4LHA Series