71
(VI) Abnormal Smoke Exhaust
Fault Characteristics & Causes
Elimination Approaches
1. White smoke rises.
a) Water penetration exists in cylinder.
b) Water is included in fuel.
c) Fuel has too bad atomization.
a) Check and eliminate the fault.
b) Replace the fuel.
c) Clean or replace the injector.
2. Blue smoke rises.
a) Oil flees; piston ring is on backward, seized
or worn too much.
b) Clearance between valve stem and valve
guide is too large.
c) Oil seal for valve stem is damaged.
a) Adjust or replace piston ring.
b) Replace the valve.
c) Replace the oil seal.
3. Black smoke rises.
a) Diesel engine is under overload.
b) Fuel supply is delayed too much.
c) Fuel supply is excessive.
d) Air filter and exhaust pipe is clogged.
e) Valve clearance is improper; valve is sealed
incompletely.
f) Timing for fuel injection is improper.
a) Reduce the load.
b) Adjust the advance angle of fuel supply.
c) Adjust injection pump and speed governor.
d) Get rid of the dust in the air filter and exhaust pipe;
or replace element of the filter.
e) Adjust the valve clearance; in case of bad sealing
performance of the taper surface, polish the valve
f) Adjust the gear of the injection pump to align the
