Stihl Ms 270 C Owners Manual

							
40 English / USAMS 270, MS 270 C, MS 280, MS 280 CIf the engine doesn’t start:If you did not move the Master Control 
lever to “Warm Start” n quickly enough 
after the engine began to fire, the 
combustion chamber has flooded.
: Loosen knob ( 1) in direction of 
arrow.
: Remove the carburetor box 
cover ( 2).
: Pull off the spark plug boot ( 3). :
Unscrew and dry off the spark plug.
: Set the Master Control lever to 
“Stop” position 
0
:Press down the interlock lever, open 
the throttle wide and, at the same 
time, crank the engine several times 
with the starter to clear the 
combustion chamber.
: Refit the spark plug and connect the 
spark plug boot  –
reassemble the other parts.
: Set Master Control lever to “Warm 
Start”  n – even if engine is cold.
: Press in decompression valve.
: Now start the engine.
During break-in periodA factory new machine should not be run 
at high revs (full throttle off load) for the 
first three tank fillings. This avoids 
unnecessary high loads during the 
break-in period. As all moving parts 
have to bed in during the break-in 
period, the frictional resistances in the 
engine are greater during this period. 
The engine develops its maximum 
power after about 5 to 15 tank fillings.
Do not make the mixture leaner to 
achieve an apparent increase in 
power – this could damage the 
engine – see “Adjusting 
Carburetor”.
Always disengage the chain brake 
before opening the throttle. Running 
the engine at higher revs with the 
chain brake engaged (saw chain at 
a standstill) will quickly damage the 
engine and chain drive (clutch, 
chain brake).
1
146BA010 KN
2
146BA009 KN
3
Operating Instructions 
						

							
41
MS 270, MS 270 C, MS 280, MS 280 C English / USA
During operationCheck chain tension frequently
A new chain has to be retensioned more 
often than one that has been in use for 
some time.
Chain cold: 
Tension is correct when chain fits snugly 
against the underside of the bar and 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 – the chain may otherwise 
jump off the bar. 
Retension the chain – see “Tensioning 
the Saw Chain”!
Always slacken off the chain after 
finishing work. The chain contracts 
as it cools down. If it is not 
slackened off, it can damage the 
crankshaft and bearings. After long period of full-throttle 
operation
 
Allow engine to run for a short while at 
idle speed so that engine heat can be 
dissipated by flow of cooling air. This 
protects engine-mounted components 
(ignition, carburetor) from thermal 
overload.
After finishing work: Slacken off the chain if you have 
retensioned it at operating 
temperature during cutting work. 
The chain contracts as it cools 
down. If it is not slackened off, it 
could damage the crankshaft and 
bearings.
Storing your saw for a short period:
Wait for engine to cool down. To avoid 
condensation, fill the fuel tank and keep 
the machine in a dry place, well away 
from sources of ignition, until you need it 
again. 
Storing for a long period:
See “Storing the Unit”! :
Turn the bar over –  
every time you sharpen the chain  
and every time you replace the 
chain –  this helps avoid one-sided 
wear, especially at the nose and 
underside of the bar.
: Regularly clean 
the oil inlet hole  (1), 
the oilway  (2) and 
the bar groove  (3).
: Measure groove depth – 
with scale on filing gauge* – in area 
used most for cutting.
* see “Guide to Using this Manual”
Taking Care of Guide Bar
2
001BA119 KN
1 3
3 
						

							
42 English / USAMS 270, MS 270 C, MS 280, MS 280 C
If groove depth is less than specified:
:
Replace 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 
simply installing a choice of filters.
Fabric filter*For normal operating conditions and 
winter operation.Fleece filter (non-woven)*For dry and very dusty work areas.
* see “Guide to Using this Manual“If there is a noticeable loss of engine 
power
:
Loosen the knob ( 1) above the rear 
handle in the direction of the arrow.
: Remove the carburetor box 
cover ( 2).
: Clean away loose dirt from around 
the filter.
: Remove the filter. 
: Knock the filter out on the palm of 
your hand or blow it clear with 
compressed air from the inside 
outwards.
In case of stubborn dirt:
: Wash the filter components in 
STIHL universal cleaner or a clean, 
non-flammable solution (e.g. warm 
soapy water) and then dry. 
Do not use a brush to clean the fleece 
filter.
: Always replace damaged filters.
Chain 
type
Pitch Minimum 
groove 
depth
Picco 3/8“ P 0.20 (5.0 mm)
Rapid 1/4“ 0.16 (4.0 mm)
Rapid 3/8“; 0.325“ 0.24 (6.0 mm)
Rapid 0.404“ 0.28 (7.0 mm)Air Filter System Cleaning the Air Filter
1
146BA010 KN
2 
						

							
43
MS 270, MS 270 C, MS 280, MS 280 C English / USA
: Locate the filter ( 3) in position (see 
arrows).
: Fit the carburetor box cover. Exhaust emissions are controlled by the 
design of the fundamental engine 
parameters and components (e.g. 
carburation, ignition, timing and valve or 
port timing) without the addition of any 
major hardware.
Your chainsaw is equipped with one of 
the following carburetors: 
–
Intelligent Engine Management  – 
Carburetor without high speed 
screw (H). Full load range and 
maximum RPM are controlled 
electronically. 
– Carburetor with high speed  screw (H)
3
146BA011 KN
Motor Management Adjusting the Carburetor
L
LA
L
146BA014 KN
H 
						

							
44 English / USAMS 270, MS 270 C, MS 280, MS 280 CStandard Setting:Shut off the engine.
: Check the air filter and clean or 
replace if necessary.
: Check spark arresting screen* in the 
muffler and clean or replace it as 
necessary.
Turn low speed screw  (L) clockwise as 
far as stop. Then back it off one quarter 
turn.
Only machines with high speed 
screw (H)
Turn the high speed screw  (H) 
counterclockwise (max. 
3/4 turn) as far 
as stop.
* See Guide to Using this Manual
Adjusting Idle SpeedEngine stops while idling
: Check the standard setting at the 
low speed screw  (L).
: Turn the idle speed screw  (LA) 
clockwise until chain begins to run – 
then back it off one turn.
Chain runs when engine is idling
: Check the standard setting at the 
low speed screw  (L).
: Turn the idle speed screw  (LA) 
counterclockwise until chain stops 
running – then turn screw another 
turn in the same direction.
If the chain continues moving when  the engine is idling, have your saw 
checked and repaired by your 
servicing dealer. Erratic idling behavior, poor 
acceleration
:
Check the standard setting at the 
low speed screw  (L).
Idle setting too lean:
: Turn low speed screw  (L) 
counterclockwise until the engine 
runs and accelerates smoothly – 
no further than stop.
It is usually necessary to change the 
setting of the idle speed screw  (LA) 
after every correction to the low speed 
screw  (L).
Machines with Intelligent Engine 
Management 
: Run the engine for about 10 
seconds at full throttle – with the 
chain and bar mounted.
: Perform cross cut at full throttle.
L
H
146BA012 KN
L
146BA013 KN
LA
L
146BA014 KN
H 
						

							
45
MS 270, MS 270 C, MS 280, MS 280 C English / USA
Only machines with high speed 
screw (H)
Operation at High AltitudeA slight correction of the setting 
may be 
necessary if engine power is not 
satisfactory:
: Check the standard setting. 
: Warm up the engine. 
: Turn high speed screw ( H) slightly 
clockwise (leaner) – no further than 
stop.
If the  setting is too lean  there is 
a  risk of engine damage  due to 
insufficient lubrication and 
overheating. Machines with Intelligent Engine 
Management
The carburetor adjusts automatically to 
any change in operating conditions (e.g. 
cutting at high altitude). 
The automatic adjustment process can 
be speeded up as follows: 
:
Run the engine for about 10 
seconds at full throttle – with the 
chain and bar mounted. 
: Perform five uniform cross cuts at 
full throttle. :
If the engine is low on power, check 
the spark arresting screen in the 
muffler.
: Allow muffler to cool down.
Remove the screw  (1).
Pull out spark arresting screen  (2).
: Clean spark arresting screen if 
necessary – if screen is damaged or 
coked up, fit a new one.
: Refit the spark arresting screen.
: Insert screw and tighten down.
* see “Guide to Using this Manual”
Spark Arresting Screen*
in Muffler
146BA008 KN
1
2 
						

							
46 English / USAMS 270, MS 270 C, MS 280, MS 280 C
Wrong fuel mix (too much engine oil in 
the gasoline), a dirty air filter and 
unfavorable running conditions (mostly 
at part throttle etc.) affect the condition of 
the spark plug. These factors cause 
deposits to form on the insulator nose 
which may result in trouble in operation. If engine is down on power, difficult to 
start or runs poorly at idling speed, first 
check the spark plug.
:
Remove spark plug – see Starting / 
Stopping the Engine.
: Clean dirty spark plug.
: Check electrode gap ( A) and 
readjust if necessary – see 
Specifications.
: Use only resistor type spark plugs 
of the approved range.
Rectify problems which have caused 
fouling of spark plug: 
: Too much oil in fuel mix.
: Dirty air filter.
: Unfavorable running conditions, 
e.g. operating at part load.
Fit a new spark plug after approx. 
100 operating hours  
or earlier if the electrodes are badly 
eroded. To reduce the risk of fire and burn 
injury, use only spark plugs 
authorized by STIHL. Always press 
spark plug boot (
2) snugly onto 
spark plug terminal ( 1) of the proper 
size. (Note: If terminal has 
detachable SAE adapter nut, it must 
be attached.) 
A loose connection between spark 
plug boot and ignition wire 
connector in the boot may create 
arcing that could ignite combustible 
fumes and cause a fire.Checking the Spark Plug
000BA002 KN
000BA036 TR
1 
						

							
47
MS 270, MS 270 C, MS 280, MS 280 C English / USA
: Remove the screws ( 1). 
: Push the hand guard upward.
: Pull the underside of the fan cover 
away from the fan housing and 
remove it downward.
: Use a screwdriver or suitable pliers 
to remove the spring clip ( 2) from 
the starter post.
: Carefully  remove the rope rotor 
with washer ( 3) and pawls ( 4) – do 
not pull the rewind spring out of the 
housing – take care to avoid injury.
Starter Grip without ElastoStart: Use a screwdriver to pry the rope 
out of the starter grip.
: Remove the remaining rope from 
the rotor and grip.
: Thread the new rope through the 
starter grip and tie a simple 
overhand knot.
: Pull the knot back into the grip.
Starter Grip with ElastoStart* :Ease the cap ( 5) out of the starter 
grip.
: Remove the remaining rope from 
the rotor and grip.
: Thread the new rope through the 
starter grip and tie a simple 
overhand knot. 
: Pull the knot back into the grip.
: Refit the cap in the grip.
* see “Guide to Using this Manual”
Replacing Starter Rope 
and Rewind Spring
1
11 1
1
146BA017 KN
4
4
3
2
001BA096 KN
146BA020 KN
5
135BA000 KN146BA018 KN 
						

							
48 English / USAMS 270, MS 270 C, MS 280, MS 280 CAll Versions:Thread the rope through the top of 
the guide bushing ( 6), pull it through 
the rotor ( 7) and secure it with a 
simple overhand knot. 
: Coat rope rotor bearing bore with 
resin-free oil.
: Slip rotor over the starter post ( 8) – 
turn it back and forth to engage 
anchor loop of the rewind spring. :
Fit the pawls ( 4) in the rope rotor.
: Fit the washer ( 3) on the starter 
post.
: Use a screwdriver or suitable pliers 
to install the spring clip ( 2) on the 
starter post and engage it on the 
pawls’ pegs – the spring clip must 
point clockwise as shown in the 
illustration.
Tensioning the Rewind Spring: Make a loop in the starter rope and 
use it to turn the rope rotor six full 
revolutions in the direction of the 
arrow. :
Hold the rotor steady – pull out and 
straighten the twisted rope.
: Release the rope rotor.
: Let go of rope slowly so that it winds 
onto the rotor.
The starter grip must locate firmly in the 
rope guide bushing. If the grip droops to 
one side: Increase spring tension by 
adding one more turn.
When the starter rope is fully extended it 
must still be possible to rotate the rotor 
another half turn. If this is not the case, 
the spring is overtensioned and could 
break. Take one turn of rope off the rotor 
in such a case.
: Fit the fan cover on the fan housing. 
8 7
146BA019 KN
6
4
4
3
2
001BA096 KN146BA007 KN 
						

							
49
MS 270, MS 270 C, MS 280, MS 280 C English / USA
Replacing a Broken Rewind 
Spring:
Remove the rope rotor. 
The bits of spring might still be 
under tension and could fly apart 
when you take them out of the fan 
cover. To reduce risk of injury, wear 
eye and face protection and work 
gloves.
: Use a screwdriver to carefully 
remove the parts of the spring.
: Lubricate the new spring with a few 
drops of non-resinous oil. :
Place the replacement spring with 
frame in the fan cover – the spring 
loop must engage the lug in the fan 
cover.
: Apply a suitable tool (screwdriver, 
punch or similar) to the recesses 
(arrows) and push the spring into its 
seat in the fan cover – the spring 
slips out of the frame in this process.
: Reinstall the rope rotor, tension the 
rewind spring, fit the fan cover and 
secure in position with the screws. For periods of about 3 months or longer:
:
Drain and clean the fuel tank in a 
well ventilated area.
: Dispose of remaining fuel and 
cleaning solution properly in 
accordance with local 
environmental requirements.
: Run engine until carburetor is dry, 
this helps prevent the carburetor 
diaphragms sticking together.
: Remove the saw chain and guide 
bar, clean them and spray with 
corrosion inhibiting oil.
: Thoroughly clean the unit, 
pay special attention to the cylinder 
fins and air filter.
: If you use a biological chain and bar 
lubricant, e.g. STIHL BioPlus, 
completely fill the chain oil tank.
: Store the unit in a dry and high or 
locked location, out of the reach of 
children and other unauthorized 
persons.
001BA103 KN
Storing the Machine