SERVICE MANUAL
ROBERT BOSCH MODEL MW INJECTION PUMP
Section 11
When the control lever contacts the low idle stop, the
injection pump is in the low idle speed position. Low idle
speed is changed by moving the low idle adjustment
screw and should be adjusted with the engine at
operating temperature. To compensate for parasitic
loads which affect low idle speed, the low idle speed
should be set slightly higher so engine speed will be
within specifications when load is applied. Examples of
major parasitic loads are mixer drums and automatic
transmissions.
RQV GOVERNOR AND ANEROID (Figure 17)
Low idle speed can be adjusted on the engine as
described in the on-engine repairs section. If diagnostic
testing confirms that any other adjustment is indicated,
follow the current warranty procedures to resolve the
problem.
To replace a leaking aneroid diaphragm, the injection
pump must be removed, the new diaphragm installed
and the injection pump recalibrated. DO NOT ATTEMPT
TO
REPLACE
THE
ANEROID
WITHOUT
RE-
CALIBRATING THE INJECTION PUMP. SEEMINGLY
SMALL
CHANGES
TO
THE
INJECTION
PUMP
CONTROL RACK SETTINGS CAN DESTROY THE
ENGINE.
Figure 17. - RQV Governor and Aneroid
ON-ENGINE INJECTION PUMP REPAIRS
REMOVAL
CLEANLINESS IS OF UTMOST IMPORTANCE WHEN
SERVICING FUEL INJECTION SYSTEMS. ALWAYS
CLEAN ENGINE BEFORE INJECTION PUMP IS
REMOVED
OR
DISCONNECTING
FUEL
LINES.
ALWAYS
PLUG
OR
CAP
ANY
OPENING
TO
PREVENT DIRT, PAINT CHIPS OR OTHER FOREIGN
MATERIAL FROM ENTERING THE FUEL SYSTEM.
Barrel to plunger clearances are approximately one
hundred millionths of an inch (0.0001000 inches).
Normally the difference between a serviceable and a
worn out barrel and plunger assembly is that dirt entered
the fuel system and caused minute wear between the
barrel and plunger.
Thorough
cleaning
prior
to
disassembly
and
an
understanding that any dirt entering the injection pump
causes damage is essential to obtaining long fuel system
life.
NOTE: Prior to injection pump removal, conduct the
diagnostic checks and adjustments found in the
appropriate diagnostic manual.
CGES-185-3
PRINTED IN UNITED STATES OF AMERICA
Page 14
