26
English / USA
FS 300, FS 350, FS 400, FS 450, FS 480
This engine is certified to operate on 
unleaded gasoline and the STIHL two-
stroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of high-
quality gasoline and quality two-stroke 
air cooled engine oil.
Use mid-grade unleaded gasoline with a 
minimum octane rating of  89 (R+M/2). If 
the octane rating of the mid-grade 
gasoline in your area is lower, use 
premium unleaded fuel. 
Fuel with a lower octane rating may  
increase engine temperatures. This, in 
turn, increases the risk of piston seizure 
and damage to the engine.
The chemical composition of the fuel is 
also important. Some fuel additives not 
only detrimentally affect elastomers 
(carburetor diaphragms, oil seals, fuel 
lines, etc.), but magnesium castings and 
catalytic converters as well. This could 
cause running problems or even 
damage the engine. For this reason 
STIHL recommends that you use only 
nationally recognized high-quality 
unleaded gasoline!
Use only STIHL two-stroke engine oil or 
equivalent high-quality two-stroke 
engine oils that are designed for use 
only in air cooled two-cycle engines. 
We recommend  STIHL 50:1 two-stroke 
engine oil since it is specially formulated 
for use in STlHL engines.
Do not use BIA or TCW rated (two-
stroke water cooled) mix oils or other 
mix oils that state they are for use in both 
water cooled and air cooled engines 
(e.g., outboard motors, snowmobiles, 
chainsaws, mopeds, etc.).
Take care when handling gasoline. 
Avoid direct contact with the skin and 
avoid inhaling fuel vapor. When filling at 
the pump, first remove the canister from 
your vehicle and place the canister on 
the ground before filling. Do not fill fuel 
canisters that are sitting in or on a 
vehicle.
The canister should be kept tightly 
closed in order to avoid any moisture 
getting into the mixture.
The machine‘s fuel tank and the canister 
in which fuel mix is stored should be 
cleaned as necessary.
Fuel mix ages
Only mix sufficient fuel for a few days 
work, not to exceed 3 months of storage. 
Store in approved fuel-canisters only. 
When mixing, pour oil into the canister 
first, and then add gasoline. Close the 
canister and shake it vigorously by hand 
to ensure proper mixing of the oil with 
the fuel.   
Dispose of empty mixing-oil canisters 
only at authorized disposal locations.
Fuel
Gaso-
line
Oil (STIHL 50:1 or 
equivalent high-quality oils)
US gal. US fl.oz
12.6
2 1/2 6.4
512.8