Fuel - Stihl MS 391 Safety Manual

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Fuel

Your engine requires a mixture of
gasoline and engine oil.
For health reasons, avoid direct
skin contact with gasoline and
avoid inhaling gasoline vapor.
STIHL MotoMix
STIHL recommends the use of STIHL
MotoMix. This ready-to-use fuel mix
contains no benzol or lead, has a high
octane rating and ensures that you
always use the right mix ratio.
STIHL MotoMix is specially formulated
for use in STIHL engines and
guarantees a long engine life.
MotoMix is not available in all markets.
Mixing Fuel
Unsuitable fuels or lubricants or
mix ratios other than those
specified may result in serious
damage to the engine. Poor
quality gasoline or engine oil may
damage the engine, sealing rings,
hoses and the fuel tank.
Gasoline
Use only high-quality brand-name
gasoline with a minimum octane rating
of 90 – leaded or unleaded.
If your machine is equipped with a
catalytic converter, you must use
unleaded gasoline.
16
A few tankfuls of leaded gasoline
will greatly reduce the efficiency of
the catalytic converter.
Engine Oil
Use only quality two-stroke engine oil.
We recommend STIHL two-stroke
engine oil since it is specially
formulated for use in STIHL engines
and guarantees a long engine life.
If STIHL two-stroke engine oil is not
available, use only quality two-stroke oil
designed for use in air-cooled engines.
Do not use oils designed for water-
cooled engines or engines with a
separate lubricating system (e.g.
conventional four-stroke engines).
Use only STIHL 50:1 two-stroke
engine oil for the fuel mix in models with
a catalytic converter.
Mix Ratio
STIHL 50:1 two-stroke engine oil: 50
parts gasoline to 1 part oil
Examples
Gasoline STIHL engine oil 50:1
Liters Liters (ml)
1 0,02 (20)
5 0,10 (100)
10 0,20 (200)
15 0,30 (300)
20 0,40 (400)
25 0,50 (500)
Other brand-name two-stroke
engine oils: 25 parts gasoline to 1
part oil
N
Use a canister approved for storing
fuel. Pour oil into canister first, then
add gasoline and mix thoroughly.
Storing Fuel
Store fuel only in approved safety-type
fuel canisters in a dry, cool and safe
location protected from light and the sun.
Fuel mix ages – only mix sufficient fuel
for a few weeks work. Do not store fuel
mix for longer than 3 months. Exposure
to light, the sun, low or high
temperatures can quickly make the fuel
mix unusable.
N
Thoroughly shake the mixture in the
canister before fueling your
machine.
Pressure may build up in the
canister – open it carefully.
N
Clean the fuel tank and canister
from time to time.
Dispose of remaining fuel and cleaning
fluid properly in accordance with local
regulations and environmental
requirements.
MS 311, MS 391