MS 661
English
23
N Fold the grip down so that it is flush 
with the top of the cap.
Tank cap is locked.
If the tank cap cannot be locked in the 
fuel tank opening
Bottom of cap is twisted in relation to 
top.
N Remove the cap from the fuel tank 
and check it from above.
N Place the cap on the opening and 
rotate it counterclockwise until it 
engages the filler neck.
N Continue rotating the cap 
counterclockwise (about a quarter 
turn) – this causes the bottom of the 
cap to be turned to the correct 
position.
N Turn the cap clockwise and lock it in 
position – see section on "Closing".
For automatic and reliable lubrication of 
the chain and guide bar – use only an 
environmentally compatible quality 
chain and bar lubricant. Rapidly 
biodegradable STIHL BioPlus is 
recommended.
NOTICE
Biological chain oil must be resistant to 
aging (e.g. STIHL BioPlus),  since it will 
otherwise quickly turn to resin. This 
results in hard deposits that are difficult 
to remove, especially in the area of the 
chain drive and chain. It may even cause 
the oil pump to seize.
The service life of the chain and guide 
bar depends on the quality of the 
lubricant. It is therefore essential to use 
only a specially formulated chain 
lubricant.
WARNING
Do not use waste oil. Renewed contact 
with waste oil can cause skin cancer. 
Moreover, waste oil is environmentally 
harmful.
NOTICE
Waste oil does not have the necessary 
lubricating properties and is unsuitable 
for chain lubrication.