Idling Speed Adjustment; Maximum Speed Setting; Anti-Stall Device - Perkins 4.108 Workshop Manual

Maximum Speed Setting
(Refer to Figs. N.18 and N.19)
The maximum speed screw (5) is set and sealed by
the manufacturers and must not be altered or tam-
pered with in any way, unless factory authority is first
obtained and any adjustments necessary are carried
out by experienced personnel. As with all seals on the
pump unauthorised removal may render the guarantee
void.
The maximum no load speed may vary according to
the vehicle or application to which it is fitted, reference
may be made to the code number stamped on the fuel
pump data plate. The last four numbers in the code
indicate the maximum no load engine speed, therefore
in the case of the following example it would be 4480
rev/min. Code Example EH39/1200/0/4480.
NOTE: If the fuel pump data plate is damaged or de-
faced so as to make it impossible to read accurately,
or if there is no code stamped on the plate you are
advised to contact your nearest C.A.V. Distributor, or
alternatively, Service Department, Perkins Engines Ltd.,
Peterborough, to obtain the required information.
NOTE: The engine must not be allowed to operate at
a speed in excess of that specified
Of
severe damage
may occur.
Ni8
Earlier Fuel Pump
Later Fuel Pump
N19
AIR CLEANERS AND FUEL SYSTEM-N.9
IDLING SPEED ADJUSTMENT
This adjustment is carried out by means of the idling
adjustments screw (4), it is carried out in conjunction
with the setting of the anti-stall device with the engine
warmed through as detailed in the following text.
Anti-Stall Device
(Refer to Figs. N.18 and N.19)
(a) Slacken the locknut (2) sufficiently to enable the
anti-stall device body (1) to be unscrewed two
complete turns.
(b) Adjust idling speed to 625 rev/min* with the idling
adjustment screw (4).
(c) Now screw down the anti-stall device body (1)
until there is a very slight increase in engine
speed, bring back half a turn and lock with the
lock nut (2).
(d) Accelerate the engine to maximum no load rev!
min and immediately return to idling.
Should the period of return from maximum rev/min
to idling exceed three seconds the device has been
screwed in too far.
However should stalling occur, then the device has
not been screwed in far enough. Therefore the neces-
sary adjustment should be made to suit whichever is
the case.
*This idling speed may vary according to application,
refer to relevant manufacturers service literature or to
Perkins Engines limited, Peterborough if in doubt.
1. Anti-stall device body
2. Anti-stall device body locknut
3. Air vent screw
4. Idling adjustment screw
5. Maximum Speed Screw