Preparations; Vacuum Test - Stihl FS 94 Instruction Manual

5.2.1

Preparations

– Remove the shroud, b 5.4
1
– Pull off the boot and unscrew the
spark plug.
– Set the piston to top dead center.
This can be checked through the
spark plug hole.
: Fit the spark plug (1) and tighten
it down firmly.
– Remove the heat shield and
gasket, fit muffler in position and
insert screws, b 5.1
Series 4149 Powerhead
2
2
: Fit the sealing plate (1)
0000 855 8106 between the
cylinder exhaust port and muffler.
: Tighten the screws (2)
moderately.
The sealing plate must completely
fill the space between the two
screws.
– Remove carburetor with fuel
hoses still attached and put it to
one side, b 10.3
1
1
2
Make sure the gasket (1) is in place.
1
1
3
2
2
: Line up the flange (1)
5910 850 4200 and fit it over the
studs (2).
: Fit the nuts (3) and tighten them
down firmly.
5.2.2

Vacuum Test

Oil seals tend to fail when subjected
to a vacuum, i.e. the sealing lip lifts
away from the crankshaft during the
piston's induction stroke because
there is no internal counterpressure.
A test can be carried out with pump
0000 850 1300 to detect this kind of
fault.
3
2
21