Stihl MS 440 - Troubleshooting Chart

80 MS 440, MS 440 C
13.1 Troubleshooting Chart
Measure resistance of
heating element at
temperature = +20 °C (68 °F)
Check thermostatic
switch
no
Replace heating
element
Does the switch open
between +6 °C (43 °F) and
+13 °C (55 °F)?
Does the switch close
between +13 °C (55 °F) and
+6 °C (43 °F)?
Carburetor heating system
in order
Resistance
approx. 8 Ohm?
no
no
yes
yes
yes
Replace thermostatic
switch
Replace thermostatic
switch