Starter Motor; Starting Circuit Test - jcb ROBOT 150 Service Manual

Section C
5 - 1

Starting Circuit Test

Before carrying out the voltmeter tests, check the battery
condition and ensure that all connections are clean and tight.
To prevent the engine starting during the tests ensure that
the engine shut off solenoid lead is disconnected at the fuel
pump.
Check the readings in the following sequence using a
voltmeter. Unless otherwise stated, the readings must be
taken with the starter switch in the 'start' position and the
transmission forward/reverse selector in neutral.
1 Connect the voltmeter across the battery terminals. The
reading in 'start' position should be 10.0 V approximately.
A low reading probably indicates a fault in the starter
motor.
Connect the voltmeter between the starter main terminal
2
A and the commutator end bracket B. In the 'Start'
position, the reading should not be more than 0.5 V
below the reading obtained in Test 1.
3 Connect the voltmeter between the solenoid terminal C
and a good earth. Minimum reading in 'start' position:
8.0 V.
9803/8500
Electrics

Starter Motor

If the reading is less than specified, connect the voltmeter
between the neutral start relay terminal D and earth. An
increase in reading to 8.0 V indicates a fault in the wiring
from the start relay to the solenoid. If the reading between
terminal D and earth is below 8.0 V, connect the voltmeter
between terminal E and earth. An increase in the reading to
8.0 V indicates either a faulty start relay or a relay solenoid.
Check also the solenoid earth connection.
If the reading between E and earth is less than 8.0 V, the
fault must be in either the starter switch (terminals F and G)
or in the wiring between the solenoid, starter switch, and the
start relay.
4 Connect the voltmeter between the battery negative and
starter earth connection B. The reading in the 'start'
position should be practically zero.
If the reading is appreciably above zero, a high
resistance in the earth lead or connections is indicated.
5 Connect the voltmeter between battery positive and the
starter main terminal A. With the starter switch 'off', the
voltmeter should indicate battery voltage, but it should
fall to practically zero when the switch is turned to the
'on' position.
If the reading is appreciably above zero, a high
resistance is present in the insulated lead or in the
solenoid. Connect the voltmeter between the battery
positive and solenoid connection H. If the voltmeter now
reads zero with the switch closed, the fault is in the
solenoid.
Section C
5 - 1
08320A
Issue 1