Testing; Complete System; Heating Element; Thermostatic Switch - Stihl MS 460 Service Manual

13.1

Testing

Complete system

The generator and heating element
are checked in the following test
which should be performed at an
ambient temperature of at least
+ 20 °C (68 °F).
If the temperature is lower than
+ 13 °C (55 °F), the thermostatic
switch may close and produce false
readings.
Test the thermostatic switch
separately.
– Remove the filter base, b 12.1
– Set the ohmmeter to measuring
range "W".
: Clip one of the two test leads to
the carburetor body and the other
to a cylinder fin (ground).
– If the system is in good condition
the ohmmeter will indicate about
8 W in measuring range "W".
If the reading obtained is outside
this tolerance, test each component
separately.
MS 460, MS 460 C

Heating element

– Disconnect pin and socket
connector to heating element.
: Clip one test lead to the metal of
the heating element, and the
other test lead to the wire that
goes to the heating element.
– If the heating element is in good
condition the ohmmeter will show
a reading of about 8 W in
measuring range "W".
If the reading obtained is outside
this tolerance, install a new heating
element.

Thermostatic switch

– Disconnect pin and socket
connector to thermostatic switch.
: Clip one test lead to the metal of
the heating element, and the
other test lead to the wire that
goes to the thermostatic switch.
At temperatures above + 20 °C
(68 °F), the ohmmeter must indicate
an infinitely high value in measuring
range "W".
Cool the switch down to below
+ 6 °C (42 °F). The ohmmeter must
indicate a value of about 0.5 W in
measuring range "W". If a higher
value is indicated, install a new
thermostatic switch.
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