Stihl BR 500 - Starting; During Operation; Holding and Controlling the Power Tool

8 BR 500, BR 550, BR 600
4.3 Carburetor
Condition Cause Remedy
Carburetor floods, engine stalls Inlet needle not sealing. Foreign
matter in valve seat or cone
damaged
Remove and clean or replace inlet
needle, clean fuel tank, pickup
body and fuel line if necessary
Inlet control lever sticking on
spindle
Free off inlet control lever
Helical spring not located on nipple
of inlet control lever
Remove inlet control lever and refit
correctly
Perforated disc on diaphragm is
deformed and presses constantly
against inlet control lever
Fit new metering diaphragm
Inlet control lever too high (relative
to design position)
Set inlet control lever flush with
upper face of housing
Poor acceleration Idle jet too lean Turn low speed screw (L)
counterclockwise (richer) no further
than stop
Main jet too lean Turn high speed screw (H)
counterclockwise (richer) no further
than stop
Inlet control lever too low (relative
to design position)
Set inlet control lever flush with
upper face of housing
Inlet needle sticking to valve seat Remove inlet needle, clean
and refit
Diaphragm gasket leaking Fit new diaphragm gasket
Metering diaphragm damaged or
shrunk
Fit new metering diaphragm
Impulse hose damaged or kinked Fit new impulse hose
RA_452_00_01_02.book Seite 8 Donnerstag, 16. Februar 2012 11:52 11