Stihl FS 80 Service Manual

54 FC 75, FC 85, FH 75, FS 75, FS 80, FS 85, HL 75, KM 85, KW 85
Correct operation of the carburetor
is only possible if atmospheric
pressure and internal fuel tank
pressure are equal at all times. This
is ensured by the tank vent.
In the event of trouble with the
carburetor or the fuel supply
system, always check the tank vent
and replace it if necessary.
Check function by performing
pressure and vacuum tests on fuel
tank via the fuel hoses.
Equalization of pressure from the
outside inwards takes place through
the hole in the filler cap, the sintered
filter, the valve and the holes in the
cap.
VA
936RA175
Equalization of pressure from the
inside outwards takes place through
the hole in the cap, the holes in the
valve body, the sintered filter and
the hole in the filler cap.
VA
936RA176
Testing
– Remove the shroud, b 5.1
: Pull fuel hose (1) off the elbow
connector on the fuel pump
flange.
VA
936RA165
1
2
: Pull the fuel hose (2) off the
elbow connector on the
carburetor.
: Seal fuel hose (1) with a suitable
plug.
: Connect pressure hose of
carburetor/crankcase tester
1106 850 2905 to fuel hose (2).
: Close the vent screw (1) on the
rubber bulb (2).
: Pump in air with the rubber bulb
(2) until the pressure gauge (3)
shows a reading of about 0.8 bar.
This pressure must drop gradually.
VA
249RA012
2
1
3
If it remains constant, the tank vent
is faulty or needs to be cleaned.
– Disconnect the carburetor/
crankcase tester 1106 850 2905
from the fuel hose.
: Push the fuel hose (1)
1110 141 8600 onto the
nipple (2) 0000 855 9200.
VA
143RA172
2 1
9.5 Tank Vent

Stihl FS 80 Specifications

General

Brand	Stihl
Model	FS 80
Category	Trimmer
Language	English