Mitsubishi S12U User Manual

Chapter 9 TROUBLESHOOTING
9-8
Engine Produces Large Amount of Smoke While in Operation
Engine Operates at High Speed and Does Not Stop
Table 9-6 Engine produces large amount of smoke while in operation
Problem Cause Remedy
A
Engine emits excessive white
exhaust smoke.
(1) Severe knocking
Fuel injection timing too
advanced
Refer to C-(1) in Table 9-2.
(2) Knocking produced only in cylinders with insufficient compression
Low engine compression Refer to C-(3) in Table 9-2.
(3) Improper fuel
a Water contained in fuel
Open drain cock and check.
Remove water or change fuel.
(4) Other
a Large amount engine oil rising
above pistons
Inspect and repair or replace as
described in F in Table 9-5.
b Engine too cold, resulting in
poor combustion
Inspect temperature regulator,
and adjust it properly to prevent
overcooling.
c Engine operating too long with
no load
Unburned oil is trapped in
exhaust pipe. White smoke stops
after engine is operated under
load.
B
Engine emits excessive black
exhaust smoke.
(1) Minor knocking
a Injection timing too retarded Refer to C-(1) in Table 9-2.
(2) Other
a Excessive amount of injected
fuel
Check if fuel injection pump rack
set screw or bolt is loose, and
repair.
b Fuel injection not uniform
Inspect, and repair or replace as
described in C-(2) in Table 9-4.
c Improper spray of fuel by fuel
injection nozzles
Inspect, and repair or replace as
described in C-(2) in Table 9-4.
d Low engine compression
Inspect, and repair or replace as
described in C-(2) in Table 9-4.
e Large amount engine oil rising
above pistons
Inspect and repair or replace as
described in F in Table 9-5.
Table 9-7 Engine operates at high speed and does not stop
Problem Cause Remedy
Fuel injection pump does not set
to no-injection condition.
Link between fuel increase/
decrease lever and governor fail-
ing to return smoothly to original
position
Check if link returns without
catching, and repair if necessary.
a Loose control link lever
Repair if rack does not move in
connection with governor lever.
b Sticking of rack disallowing its
return to original position
Check rack for smoothness, and
disassemble and repair.

Mitsubishi S12U Specifications

General

Brand	Mitsubishi
Model	S12U
Category	Engine
Language	English