53
Injectors
The job of the injectors is to atomize and spray the
fuel, metered precisely by the injection pump, into
the engine’s combustion chambers. This injection
takes place under extremely high pressure so that
atomization and combustion of the fuel takes place
as effectively as possible.
Each injector basically comprises a nozzle holder
and a nozzle (jet). When the fuel pressure increases
to a set value (opening pressure), the nozzle needle
(7), which is pressed in its seat by the pressure
spring (4), is raised, and atomized fuel is sprayed
into the engine through carefully calibrated holes in
the nozzle body. The tension of the pressure spring
determines the opening pressure of the injector.
The injectors should be checked regularly by author-
ized personnel, refer to maintenance schedule. An
incorrect opening pressure or faulty nozzle will result
in smoky exhaust gases and lower engine output.
Maintenance – Fuel system
Fuel pre-filter. Checking/draining
Check the fuel filter and drain off any water and
contaminants through the drain plug(s) (5). See
illustration on next page.
The engine should be off and allowed to stand for a
few hours before carrying out this check. Reinstall
the plugs.
Injectors
1.
Pressure line connection
2.
Connection for fuel leak-off pipe
3.
Shims for setting the opening
pressure
4.
Thrust spring
5.
Thrust pin
6.
Jet
7.
Nozzle needle
Fuel pre-filter. Installing new insert(s)
Double filter: As a rule, the filter inserts should be
replaced when the pressure gauge indicates a
vacuum of 6–10 in. Hg* (idle) or 16–20 in. Hg
respectively, (max. rpm, loaded engine). However,
filters must be replaced after every 1000 operating
hours.
Close the fuel cocks at the tank before dismantling
the single filter or replacing the inserts of the double
filter with the engine off.
Double filter: If inserts are to be replaced when the
engine is running, shut off the filter unit with the insert
to be replaced by turning the valve handle (1) to the
horizontal position. See illustration on next page.
* Note: In. Hg = Inches of mercury.
Positions of the valve knob
Up: Normal operating position. Both filters are
on-line.
Right: Left-hand filter insert can be replaced.
Left: Right-hand filter insert can be replaced.
Down: Both filters are off line.
1. Position a container under the fuel filter. Remove
the cover (4) and lift out the insert by rotating it.
See illustration on next page.
2. Drain off any water or contaminants through the
drain plug (5).
3. Install new filter insert and fill container with clean
diesel oil. Install the cover with a new gasket and
tighten by hand.
Note. Moisten the gasket with diesel oil before
installation. Cleanliness! The fuel in the system
must not become contaminated.
4. Double filter: Replace the other filter insert in
the same way.
5. Dry off any diesel fuel spilt on the heat shield.
6. Double filter: Both filter units on-line (turn the
knob (1) up to the vertical position).
7. Open the fuel cocks and check that there are no
leaks.
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Summary of Contents for TAMD63L
Page 1: ...INSTRUCTION BOOK TAMD63L P TAMD71B TAMD73P WJ TAMD74C L P ...
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Page 124: ...7740156 0 English 6 2000 AB Volvo Penta SE 405 08 Göteborg Sweden www volvopenta com ...