Leakage Test; Preparations - Stihl MS 261 User Manual

1
2
2
: Carefully place the muffler (1) in
position.
: Check the position of the gasket
and fit the screws (2).
– Insert the screws (2) – do not
tighten down yet.
2
1
: Insert the screws (1) – do not
tighten down yet.
: Tighten down screws (1) and (2)
firmly.
– Use a blunt tool to push home the
new plugs
– take care not to damage the
plugs.
6.2

Leakage Test

Defective oil seals and gaskets or
cracks in castings are the usual
causes of leaks. Such faults allow
supplementary air to enter the
engine and upset the fuel-air
mixture.
36
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
first and then the pressure test.
The engine can be checked
thoroughly for leaks with the pump
0000 850 1300.
6.2.1

Preparations

– Remove the shroud, b
2
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.
– Remove the decompression
valve, b 6.9
: Fit the plug (1) 1122 025 2200
and tighten it down firmly.
: Fit the spark plug (2) and tighten
it down firmly.
b 6.4
1
2
2
1
– Pry out the plugs.
– do not re-use plugs that have
been removed.
: Loosen the screws (1) and (2).
1
: Fit the sealing plate (1)
0000 855 8106 on the cylinder
exhaust port between the gasket
and muffler and tighten down the
screws moderately.
The sealing plate must completely
fill the space between the two
screws.
– Remove the carburetor, b
1
: Make sure the washer (1) is in
place.
MS 261, MS 261 C
2
1
b 12.5