Stihl BR 500 - Preparations; Vacuum Test

36 BR 500, BR 550, BR 600
– Remove the carburetor, b 6.2.2
– Loosen the muffler mounting
screws, b 7.6
: Seal the impulse hose (1) with a
suitable plug.
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: Mount the test flange
1119 850 4201 (2) to the
manifold with suitable screws.
: Slide the sealing plate
0000 855 8106 (1) between the
muffler and cylinder exhaust port.
– Tighten the muffler mounting
screws moderately.
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The sealing plate must completely
fill the space between the screws.
– Set the piston to top dead center.
– Perform vacuum test, b 7.8.2
– Perform pressure test, b 7.8.3
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 the
vacuum pump to detect this kind of
fault.
– Carry out the preparations,
b 7.8.1
: Connect suction hose (1) of
vacuum pump 0000 850 3501 to
nipple (arrow) of the test flange.
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: Close the vent screw (1) on the
pump.
: Operate the lever (2) until the
pressure gauge (3) indicates a
vacuum of 0.5 bar.
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7.8.1 Preparations 7.8.2 Vacuum Test
RA_452_00_01_02.book Seite 36 Donnerstag, 16. Februar 2012 11:52 11