Operation Manual

36 MS 241 C
: Washer (1) must be fitted
: Orient flange (1) 1118 850 4200
and push it onto the studs
: Fit flange (1) 1118 850 4200
: Tightly screw on nuts (2)
6.2.2 Vacuum test
Oil seals tend to fail when subjected
to a vacuum. In other words, the
sealing lip lifts away from the
crankshaft during the piston's
induction stroke because there is no
internal counterpressure.
This kind of fault can be detected by
testing with pump 0000 850 1300.
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: Push the hose (1) of pump
0000 850 1300 onto the
connector (arrow)
: Slide ring (2) to the left
– Vacuum test
: Operate lever (3) until the
pressure gauge (4) indicates a
vacuum of 0.5 bar
If the vacuum reading remains
constant, or does not decrease by
more than 0.3 bar within 20
seconds, it may be assumed that
the oil seals are in good condition.
If the vacuum in the crankcase is
reduced further, the oil seals must
be replaced, b 6.3.
– After testing, slide the ring on the
pump back to the right to vent the
pump.
– Continue with pressure test,
b 6.2.3
6.2.3 Pressure test
The same preparatory steps are
required as for the vacuum test,
b 6.2.2.
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: Slide ring (1) to the right
– Pressure test
: Operate the lever (2) until the
pressure gauge (3) indicates a
pressure of 0.5 bar. If this
pressure remains constant for at
least 20 seconds, the engine
crankcase is airtight
– If the pressure drops, the leak
must be located and the defective
part replaced
To find the leak, coat the suspect
area with soapy water and
pressurize the crankcase. Bubbles
will appear if a leak exists.
– After testing, slide the ring on the
pump to the left to vent the pump
– disconnect the hose
– Remove flange 1118 850 4200
on intake elbow
– Refit carburetor, b 8.4
– Remove flange 5910 855 4201
and sealing plate 0000 855 8106
– Refit the muffler, b 6.1
– Press in new stoppers straight
with a blunt tool
– Do not damage stoppers
– Reassemble remaining parts in
reverse order
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