Yanmar 3YM30 Sevice Manual page 70

TROUBLE AND TROUBLESHOOTING
(I-1) Increase injection pressure.
(I-2) Replace.
(I-3) Disassemble and lap.
(I-4) Disassemble and repair.
(I) Faulty fuel injection valve
(1) Low injection pressure
(2) Damaged fuel valve spring
(1) Excessive quantity of fuel
is ejected from fuel pump
(III) Excessive quantity of fuel injected each time
(III-1) Adjust pump adjustment rack.
(II-1) Delay injection timing.
(II-2) Adjust standard injection pressure.
(II) Faulty fuel injected
(3) Sticking of valve needle
(4) Faulty injection spray
(1) Insufficient cooling water
(2) Excess piston clearance
(3) Excess bearing clearance
(IV-1) Check cooling water pump and lap valves.
(IV-2) Replace.
(IV-3) Replace.
(IV-4) Replace with good fuel oil.
(IV-5) Replace with good fuel oil.
(IV-6) Check and repair.
(1) Early fuel injection
(2) Fuel pressure is too high
(4) Poor quality fuel oil
(5) Water mixed in fuel oil
(6) Incorrect pressure
(IV) Miscellaneous
Chart 6
KNOCKING
KNOCKING