43FS 90, FS 90 R
English / USA
To reduce the risk of fire and burn 
injury, use only spark plugs 
authorized by STIHL. Always press 
spark plug boot (2) snugly onto  
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.
: Check grease level regularly - about 
every 25 hours of operation.
: Unscrew the filler plug (1).
: If no grease can be seen on the 
inside of the filler plug, screw the 
tube (2) of STIHL gear lubricant for 
brushcutters - see “Special 
Accessories” - into the filler hole.
: Squeeze up to 1/5 oz (5 g) grease 
into the gear housing.
Do not completely fill the gear 
housing with grease. 
: Refit the filler plug and tighten it 
down firmly.
Replacing the starter rope
: Move slide control in direction of 
c – arrow to STOP-O.
: Take out the screws (1).
: Lift the starter cover (2) off the 
housing.
1
2
002BA071 KN
Lubricating the 
Gearbox
1
233BA010 KN
2
Replacing Starter Rope 
and Rewind Spring
1
1
249BA061 KN
2
1