Abstract

An electromagnetic fuel injector has an axially extending hollow, tubular guide pin fixed in one end of the through bore of a solenoid pole piece and slidably received in one end of a cup-shaped armature whereby to axially guide the armature during its movement relative to the solenoid pole piece and is engageable at one end thereof with a surface of the armature whereby to serve as an abutment stop for the armature so as to establish a predetermined minimum working air gap between the opposed working surfaces of the armature and an associated solenoid pole piece. An armature return spring is loosely received in the tubular guide pin has one end thereof in abutment with the armature to normally bias the armature in an axial direction away from the solenoid pole piece and has its opposite end in abutment against an externally accessible abutment screw threaded into the opposite end of the bore of the solenoid pole piece and having an end therefore extending into the tubular guide pin so as to abut against the opposite end of the armature return spring whereby the force of the armature return spring can be adjusted as desired.