Leakage Test - Stihl FS 94 Instruction Manual

3
1
4
: Push the upper edge of the heat
shield (1), tab (2) first, between
the wall of the air guide
shroud (3) and cylinder and its
lower edge between the hook (4)
and the cylinder.
: Push the heat shield (1) home
until its holes line up with the
holes in the cylinder.
20
2
2
1
2
: Carefully fit the muffler (1) in
position and insert the screws (2)
– do not tighten down yet.
: Check that gasket and heat
shield are properly positioned.
: Insert and tighten down the
screws (2) firmly.
– Reassemble all other parts in the
reverse sequence.
5.2

Leakage Test

Defective oil seals and gaskets or
cracks in castings are the usual
causes of leaks. Such faults allow
2
supplementary air to enter the
engine and upset the fuel-air
mixture.
This makes adjustment of the
prescribed idle speed difficult, if not
impossible.
Moreover, the transition from idle
speed to part or full throttle is not
smooth.
Always perform the vacuum test
1
first and then the pressure test.
The engine can be checked
2
thoroughly for leaks under vacuum
and pressure with the pump
0000 850 1300.
Series 4149 Powerhead