Stihl MS 391 User Manual

67MS 311, MS 391
– Place the oil pump (1) in position.
: Fit and tighten down the screws
(2) firmly.
– Connect the oil suction hose to
the oil pump.
– Push the worm fully home.
: Fit the cover washer (1) so that
the word TOP (arrow) faces
outwards.
– Check adjustment of oil pump
and readjust if necessary – see
instruction manual.
– Reassemble all other parts in the
reverse sequence.
4903RA184 TG
1
2
2
4903RA270 TG
1
11.4 Valve
A valve is installed in the tank wall to
keep internal tank pressure equal to
atmospheric pressure. The valve
must be replaced if it is faulty.
– Open the oil tank cap and drain
the oil tank b 1.
: Use a 6 mm drift to carefully
drive the valve out of its seat in
the housing and into the oil tank.
: Remove the old valve (1) from
the oil tank.
4903RA185 TG
219RA476 TG
1
Installing
Check correct installed position.
: Insert the valve in the housing
bore (arrow).
– Use a 6 mm drift to carefully
drive in the new valve from
outside – note installed depth.
: Installed depth of new valve:
a=1mm +/- 0.1.
– Reassemble all other parts in the
reverse sequence.
4903RA186 TG
219RA479 TG

Stihl MS 391 Specifications

General

Motor type	2-stroke motor
Chain gauge	1.6 mm
Chain pitch	3/8 \
Automatic oiling	Yes
Oil tank capacity	0.35 L
Fuel tank capacity	0.6 L
Engine displacement	64.1 cm³
Engine power	4.4 hp
Power source	Gasoline

Weight and Dimensions

Weight	6200 g