21HS 81 R, HS 81 T
English / USA
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.
Use STIHL gear lubricant for hedge
trimmers (see “Special Accessories”) to
lubricate the blade drive gear.
After about 25 hours of operation:
: Remove the screw plug (1) from the
gear housing.
: Screw the tube of grease (2) into the
filler hole.
: Roll up the end of the tube to the
next division on the scale. This
forces about 3/4oz (20g) grease into
the gearbox.
: Refit the screw plug and tighten it
down firmly.
00BA036 TR
1
Lubricating the
Gearbox
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