MS 271, MS 271 C, MS 291, MS 291 C
English
7
N To return the cap to the open 
position for installation, turn the cap 
(with the grip up) until it drops fully 
into the tank opening. Next, twist the 
cap counterclockwise as far as it will 
go (approx. 1/4 turn) – this will twist 
the base of the cap into the correct 
position for installation. Then, twist 
the cap clockwise, closing it 
normally.
N If your cap still does not tighten 
properly, it may be damaged or 
broken; immediately stop use of the 
unit and take it to your authorized 
STIHL dealer for repair.
See also the "Fueling" chapter in your 
Instruction Manual for additional 
information.
Before Operation
Take off the chain guard (scabbard) and 
inspect the chain saw for proper 
condition and operation. (See the 
maintenance chart near the end of the 
instruction manual.)
WARNING
Always check your chain saw  for proper 
condition and operation before starting, 
particularly the throttle trigger, throttle 
trigger lockout, stop switch and cutting 
attachment. The throttle trigger must 
move freely and always spring back to 
the idle position. The Master Control 
Lever / stop switch must move easily to 
STOP, 0 or †. Never attempt to modify 
the controls or safety devices.
WARNING
Check fuel system for leaks, especially 
the visible parts, e.g., filler cap, hose 
connections, manual fuel pump (only for 
chain saws equipped with a manual fuel 
pump). Do not start the engine if there 
are leaks or damage – risk of fire! Have 
the chain saw repaired by a STIHL 
servicing dealer before using it.
WARNING
Check that the spark plug boot is 
securely mounted on the spark plug – a 
loose boot may cause arcing that could 
ignite combustible fumes and cause a 
fire.
For proper assembly of the bar and saw 
chain follow the procedure described in 
the chapter "Mounting the Bar and 
Chain" of your instruction manual. 
STIHL Oilomatic saw chain, guide bar 
and sprocket must match each other in 
gauge and pitch. Before replacing any 
bar and chain, see the chapter entitled 
"Specifications" in the instruction 
manual and the chapter "Reactive 
Forces including Kickback".
Since longer bars add weight and may 
be more difficult to control, select the 
shortest bar that will meet your cutting 
needs.
WARNING
Proper tension of the chain is extremely 
important. In order to avoid improper 
setting, the tensioning procedure must 
be followed as described in your 
manual. Always make sure the 
hexagonal nut(s) for the sprocket cover 
is (are) tightened securely after 
tensioning the saw chain in order to 
secure the bar. Never start the chain 
saw with the sprocket cover loose. 
Check chain tension once more after 
having tightened the nut(s) and 
thereafter at regular intervals (whenever 
the saw is shut off). If the saw chain 
becomes loose while cutting, shut off the 
engine and then tighten. Never try to 
adjust the saw chain while the engine is 
running!
WARNING
After adjusting a saw chain, start the 
chain saw, let the engine run for a while, 
then switch engine off and recheck saw 
chain tension. Proper saw chain tension 
is very important at all times.
Left: Bottom of cap in closed posi-
tion – inner mark (1) in line 
with outer mark.
Right: Bottom of cap in correct posi-
tion for installation – inner 
mark is under the grip and 
not in line with the outer 
mark.