ENGINE DIAGNOSTIC TEST PROCEDURES
LOW IDLE (RPM)
400 Series On-Highway (with
Robert Bosch MW Pumps)
FROM FORM NO. CGED-365
LOW IDLE (RPM)*
MANUAL TRANSMISSION- NEUTRAL
AUTOMATIC TRANSMISSION - DRIVE
MIXER- DRUM ENGAGED
*Engine must be at normal operating temperature.
p Refer to "Performance Data Guidelines", in this section.
Measure Low Idle Speed
Assure linkage is adjusted as specified in Operation
Set the control lever on the pump to low idle position,
Figure 10, by moving the lever fully towards the
governor housing. The lever must contact the low
idle stop screw.
PARKING BRAKE MUST BE ENGAGED WITH
AUTOMATIC TRANSMISSION IN GEAR AND
MIXER DRUM ENGAGED (IF APPLICABLE).
With the engine running check low idle speed using
an accurate tachometer. See "Performance Data
Guidelines" in this section for specifications.
If adjustment is required, proceed as directed in Low
Idle Adjustment Procedure.
Low Idle Speed Adjustment
Loosen the lock nut with a 10 mm wrench and raise
or lower the low idle stop (bolt) with an 8 mm
Raise the stop to increase speed, lower to decrease
Tighten the lock nut when the specified speed is
NOTE: 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 the load is applied. Examples of
major parasitic loads are mixer drums and automatic
Figure 12. Low Idle Adjustment
For Robert Bosch MW Pump
Printed in United States of America