Tank Vent - Stihl MS 270 User Manual

6. Install new limiter caps, noting
that the stop lugs on the limiter
caps must line up with the
openings in the carburetor.
Limiter caps that have been
removed once are damaged and
must not be re-used.
MS 270, MS 280
12.5

Tank Vent

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 and clean the
tank vent.
Check function by performing
vacuum test on the tank via the fuel
hose.
– Remove the filter base
– see 12.1.
1
– Disconnect the fuel hose (1) from
the carburetor.
2
Connect vacuum pump (1)
0000 850 3501 to fuel hose (2)
and subject fuel tank to vacuum.
1
Equalization of pressure in the
fuel tank takes place via the tank
vent valve (1). There must be no
build-up of vacuum during the
test. In the event of a malfunction,
use a screwdriver to remove the
vent valve (1) and install a new
valve with a new sealing ring.
– Reassemble in the reverse
sequence.
1
81