If the engine fails to start, or is
difficult to start, check that the fuel pump is operating
satisfactorily. When the ignition is switched “on”, the fuel pump
should start operating. (This is confirmed by hearing the note of the
driving motor, or by feeling the slight vibrations in the body of the
If the pump is not operating, connect
a voltmeter across these cables, on the supply side, and an ammeter in
one of the leads. When the ignition is switched on, the voltmeter
reading should be 12 volts and the ammeter should read approximately 5
amperes, see Figure 15.
If the voltmeter reading is zero, one
of the leads to
the motor is open-circuit.
Low readings (for both voltage and current) indicate a high resistance
in the circuit. The wiring to the motor should, therefore, be checked.
Any other variations in voltage and
current readings indicate a faulty pump motor; possibly a defective
brush assembly or open-circuit armature winding. Remove unit for further
A high reading indicates a tight pump
or stalled motor or short-circuited armature windings. Remove for