Use clean diesel fuel for washing the parts.
Disassemble one nozzle at a time to prevent mixing of
mating parts. Exercise care to prevent damage to nozzle
parts. Inspect and clean all parts as they are
disassembled. Carbon may be scraped from the outside
of the nozzle, but be careful not to mar the edges of the
holes (orifices). When cleaning fluid is used to clean
the nozzle parts, dip the parts in diesel fuel immediately
after cleaning. This will prevent moisture from the
hands from marring the highly polished surfaces.
Reaming tools and special drills are provided for
cleaning spray nozzle holes. No drills other than those
recommended by the manufacturer should be used. The
drills are hand-operated, using a cleaning needle that is
held in place by a small chuck, called a pin vise (fig.
5-45). In performing reaming operations, remove only
the foreign matter; be particularly careful not to burr the
Diesel fuel is a hazardous material. Avoid
prolonged skin contact and wear goggles.
Keep fire and flame away. Dispose of waste
material and cleaning rags as hazardous waste.
For more information, see OPNAVINST
4110.2, Hazardous Material Control and
Q31. When should water be drained from the fuel
Q32. What is the first requirement when
disassembling an injector for cleaning?
LEARNING OBJECTIVE: Describe general
troubleshooting techniques used in the
maintenance of a diesel fuel system.
Figure 5-45.Cleaning injector spray nozzle holes.
When troubleshooting a diesel engine, keep in mind
that problems associated with one make and type of
engine (two-stroke versus four-stroke) may not occur
exactly in the same way as in another. Specifically,
particular features of one four-stroke-cycle engine
may not appear on another due the type of fuel
system used and optional features on that engine.
Follow the basic troubleshooting steps listed below
before rolling up your sleeves and trying to pinpoint a
Obtain as much information from the operator
as possible concerning the complaint.
Analyze the problem in detail first, beginning
with the smallest and simplest things.
Relate the problem symptoms to the basic
engine systems and components.
Consider any recent maintenance or repair job
that might tie into the problem.
Always double-check and think about the
problem before disassembling anything.
Solve the problem by checking the easiest and
simplest things first.
If possible, use the special tools and diagnostic
equipment at your disposal to verify acomplaint
and pinpoint the general area.
Determine the cause(s) of the problem and carry
out the repair.
Operate the engine and road test the vehicle to
confirm that the problem is corrected.
EXHAUST SMOKE COLOR
One of the easiest methods to use when
troubleshooting an engine for a performance complaint
is to monitor the color of the smoke coming from the
exhaust stack visually. There are four basic colors that
may exit from the exhaust system at any time during
engine operationwhite, black, gray, or blue. The
color of the smoke tips you off to just what and where
the problem might lie.
White smoke is generally most noticeable at
engine start-up, particularly during cold
conditions. As the combustion and cylinder
temperatures increase during the first few
minutes of engine operation the white smoke
should start to disappear which indicates the
engine is sound. However, if the white smoke