The low idle adjustment screw on the DB4 fuel injection pump is mounted on the control lever assembly. The
adjustment screw can be used to increase the idle speed to compensate for accessory loading. The low idle adjustment screw must be adjusted by an authorized service dealer and resealed.
NOTE: Never turn the idle adjusting screw out (reduce idle speed) on the speed drop governor equipped fuel injection
pump; this can result in disengagement of the throttle lever from the guide bushing.
The high idle adjustment screw (A) is sealed. The adjustment screw on the DB4 fuel injection pump is mounted
on the control level assembly. The high idle adjustment screw must be adjusted by an authorized service dealer.
The speed droop adjustment screw (B) is located above the delivery head. The fuel pump governor sensitivity can
be adjusted to increase or decrease governor regulation.
