Stihl Ms 250 C Manual

MS 250
English
39 Chain cold
Tension is correct when the chain fits 
snugly against the underside of the bar 
but can still be pulled along the bar by 
hand. Retension if necessary – see 
"Tensioning the Saw Chain".
Chain at operating temperature
The chain stretches and begins to sag. 
The drive links must not come out of the 
bar groove on the underside of the bar – 
the chain may otherwise jump off the 
bar. Retension the chain – see 
"Tensioning the Saw Chain".
NOTICE
The chain...

MS 250
English
40 If groove depth is less than specified:
NReplace the guide bar.
The drive link tangs will otherwise 
scrape along the bottom of the groove – 
the cutters and tie straps will not ride on 
the bar rails.The air filter system can be adapted to 
suit different operating conditions by 
installing a choice of filters. Changing 
the filter is quick and simple.
The saw comes standard with either a 
fabric filter or a fleece filter.
Fabric filter
For normal operating conditions and 
winter...

MS 250
English
41
NOTICE
To avoid damaging the filter, do not use 
tools for removing and installing the air 
filter.
NBlow out the filter with compressed 
air from the clean air side.
If the filter fabric is caked with dirt or no 
compressed air is available:
NWash the filter in a clean, non-
flammable solution (e.g. warm 
soapy water) and then dry.
NReinstall the air filter.Exhaust emissions are controlled by the 
design of the fundamental engine 
parameters and components (e.g. 
carburation, ignition,...

MS 250
English
42
Adjusting Idle Speed
NCarry out the standard setting.
NStart and warm up the engine.
Engine stops while idling
NTurn the idle speed screw (LA) 
clockwise until the chain begins to 
run –  then back it off 1/4 turn.
Saw chain runs while engine is idling
NTurn the idle speed screw (LA) 
counterclockwise until the chain 
stops moving –  then turn it another 
1/4 turn in the same direction.
WARNING
If the chain continues moving when the 
engine is idling, have your saw checked 
and repaired...

MS 250
English
43 NPlace fingers behind the air filter (3), 
press thumbs against the housing, 
swing the filter in the direction of the 
rear handle and remove it. 
NRemove the shutter (4).
NPull off the spark plug boot.
NUnscrew the spark plug.
Checking the spark plug
NClean the spark plug if it is dirty
NCheck the electrode gap (A) and 
readjust if necessary – see 
"Specifications"
NUse only resistor type spark plugs of 
the approved range
Correct the problems that have caused 
fouling of the...

MS 250
English
44 If engine running behavior is 
unsatisfactory even though the air filter 
is clean and the carburetor is properly 
adjusted, the cause may be the muffler.
Have the muffler checked for 
contamination (carbonization) by your 
servicing dealer.
STIHL recommends that you have 
servicing and repair work carried out 
exclusively by an authorized STIHL 
servicing dealer.For periods of 3 months or longer
NDrain and clean the fuel tank in a 
well ventilated area.
NDispose of fuel properly in...

MS 250
English
45 NUse a screwdriver to remove the E-
clip (1)
NRemove the washer (2)
NRemove rim sprocket (3) (if so 
equipped), clutch drum (4) and 
needle cage (6).
NInspect transport profile for rim 
sprocket on the clutch drum (4) – if 
there are also heavy signs of wear, 
also replace the clutch drum
NRemove clutch drum with integrated 
spur chain sprocket (5) (if so 
equipped) including needle cage (6) 
from the crankshaft – for 
powerheads with Quickstop Plus 
chain brake system, depress...

MS 250
English
46
Chain pitch
The chain pitch marking (a) is embossed 
in the area of the depth gauge of each 
cutter.
The diameter of file to be used depends 
on the chain pitch – see table 
"Sharpening tools".
The angles of the cutter must be 
maintained during resharpening.Sharpening and side plate angles
ASharpening angle
STIHL saw chains are sharpened with a 
30° sharpening angle. Ripping chains, 
which are sharpened with a 10° 
sharpening angle, are exceptions. 
Ripping chains have an X in...

MS 250
English
47
Proper sharpening
NSelect sharpening tools in 
accordance with chain pitch
NClamp guide bar if necessary
NBlock saw chain – push the hand 
guard forward
NTo advance the saw chain, pull the 
hand guard toward the handlebar: 
The chain brake is disengaged. 
With the Quickstop Plus chain brake 
system, additionally press the 
throttle trigger lockout
NSharpen frequently, removing little 
material – two or three strokes of the 
file are usually sufficient for simple 
resharpening
NGuide the...

MS 250
English
48 Saw chains with humped drive link (2) – 
upper part of the humped drive link (2) 
(with service mark) is lowered at the 
same time as the depth gauge of the 
cutter.
WARNING
The rest of the humped drive link must 
not be filed; otherwise, this could 
increase the tendency of the chain saw 
to kick back.
NRework the depth gauge so that it is 
flush with the file gaugeNAfterwards, dress the leading edge 
of the depth gauge parallel to the 
service mark (see arrow) – when 
doing this, be...