Leakage Test; Preparations - Stihl SR 430 Manual

1
: Remove the spark arresting
screen (1).
– Clean the spark arresting screen
with bushing (1) or replace if
necessary.
– Reassemble in the reverse
sequence.
– Fit the shroud, b 4.4
4.2

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.
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.
SR 430, SR 450
4.2.1

Preparations

1
– Remove the shroud, b 4.4
– Pull off the spark plug boot
vertically.
: Unscrew the spark plug (1).
– 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.
1
: Loosen the screws (arrows).
: Pull the muffler (1) out a little.
1
: Fit the sealing plate (1)
0000 855 8106 between the
cylinder exhaust port and muffler
and tighten down the screws
moderately.
The sealing plate must completely
fill the space between the two
screws.
– Remove the carburetor, b 9.5
1
Check that the gasket (1) is in
position.
1
: Fit the test flange (1)
5910 850 4200.
17