Yanmar 3YM30, Service Manual

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3. Troubleshooting
61
Malfunctions Causes Remedies
4. The nozzle or the nozzle holder
is not functioning properly
The engine cannot reach its
maximum speed 1. The governor spring is too weak
or is improperly adjusted
2. The control lever is not reaching
the maximum-speed position
3. The nozzle’s injection operation
is poor
Inspect and then repair or replace
Readjust or replace
Readjust
Repair or replace
The engine’s maximum speed is
too high 1. The governor spring is too
strong or is improperly adjust
2. The governor flyweights or
governor sleeve movement is
not smooth
Readjust or replace
Repair or replace
Idling is unstable 1. The injection quantities are not
uniform (the delivery valve is
not operating properly)
2. The governor’s idling
adjustment is improperly
adjusted
3. The plunger is worn
4. The plunger spring is broken
5. The rubber damper is worn.
6. The governor lever shaft pin is
worn excessively
7. The feed pump blades are not
operating properly
8. The regulating valve is stuck in
the open position
9. The fuel filter element is
clogged and therefore fuel oil
delivery is poor
10.The nozzle or the nozzle holder
is not functioning properly
Inspect or replace
Readjust
Replace the distributor assembly
Replace
Replace
Replace
Repair or replace
Replace
Clean or replace
Inspect and then repair or replace