130 MS 261, MS 261 C
13. Heating System
13.1 Carburetor Heating
The heating element is installed
between the filter base and
carburetor. Current is supplied via
wires to the heating element.
The heating element is controlled by
a thermostatic switch on the
underside of the carburetor.
The heating element and
thermostatic switch should be
checked if running problems occur
when the cold engine is idling or
running at part load, particularly at
temperatures below freezing.
Idling problems with a hot engine
are also an indication of a fault in the
heating element or thermostatic
switch.
13.1.1 Testing the 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 heating system as
specified in the carburetor
heating troubleshooting chart,
12.1
– Set the ohmmeter to measuring
range "Ω".
: Clip one of the two test leads to a
nut on the baffle and the other to
a cylinder fin.
– If the system is in good condition
the ohmmeter will indicate a
value of about 12 Ω in
measuring range "Ω".
If the reading obtained is outside
this tolerance, test each component
separately.
13.1.2 Testing the Heating
Element
– Remove the filter base,
5902RA512 TG
5902RA365 TG
1
: Take out the screw (1).
: Remove the heating element (2).
: Clip one test lead to the heating
element and the other to the ring
terminal.
If the heating element is in good
condition the ohmmeter will indicate
a value of about 12 Ω in measuring
range "Ω".
5902RA515 TG
2
1