Yanmar 3YM30 Sevice Manual page 72

TROUBLE AND TROUBLESHOOTING
(I-1) Replace.
(I-2) Disassemble and repair or replace.
(I-3) Lap valves.
(I-4) Tighten firmly.
(I-5) (I-6) Adjust.
(I-7) (I-8) Clean.
(I-9) Replace.
(I-10) Repair.
(I) Amount of oil supply from fuel injection pump inadequate
(1) Worn plunger
(2) Sticking of plunger
(3) Oil leakage from exhaust valve
(4) Oil leakage from joint of
high pressure pipe
(5) Faulty adjustment of fuel pump
(1) Leakage of gas from
suction/exhaust valves
(3) Worn upper part
(2) Inadequate tapper
(4) Worn piston ring
clearance
(5) Sticking of piston ring
(IV) Leakage of pressurized gas from inside cylinder
(IV-1) Lap valves.
(IV-2) Adjust.
(IV-3) Replace.
(IV-4) Replace.
(IV-5) Disassemble and repair or replace.
(II-1) Clean nozzle hole or replace.
(II-2) Lap or replace.
(II-3) Lap or replace.
(II-4) Tighten firmly.
(II-5) Replace.
(II-6) lean.
(II) Amount of fuel injection inadequate
(6) Inaccurate positioning
of adjustment rack
(7) Clogging of fuel filter
(8) Clogging of fuel oil pipe
(9) Damaged valve spring
(10) Faulty supply pump
(1) Early injection
of cylinder liner
(2) Late injection
(V) Irregular fuel injection timing
(V-1) Adjust timing to
delay injection.
(V-2) Adjust timing to
speed injection.
(III-1) Replace.
(III-2) Repair.
(1) Clogging of nozzle hole
(2) Faulty valve seat
(3) Sticking of valve needle
(4) Loose high pressure pipe
(5) Worn valve needle
(6) Clogging of filter
(1) Clogging of air filter
(VI) Clogged intake air filter
(VI-1) Clean. (VII-1) Replace with good fuel oil.
(VII-2) Clean.
(VII-3) Disassemble, check and repair.
(VII-4) Lap cooling water pump suction/exhaust valves.
(VII-5) Disassemble and clean lube oil pump and filter.
Chart 8
INSUFFICIENT POWER OUTPUT
(III) Faulty governor
(1) Damaged governor bearing
(2) Inaccurate length
of governor link
INSUFFICIENT
POWER OUTPUT
(1) Poor quality fuel oil
(2) Clogging of exhaust line
(3) Seizure of moving parts
(4) Insufficient cooling water
(5) Insufficient lube oil supplied
(VII) Miscellaneous