Checking Chain Tension; Fuel - Stihl MS 661 C-M Manual De Instrucciones

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Checking Chain Tension

Shut off the engine.
N
Wear work gloves to protect your
N
hands.
The chain must fit snugly against
N
the underside of the bar and it must
still be possible to pull the chain
along the bar by hand.
If necessary, retension the chain.
N
A new chain has to be retensioned more
often than one that has been in use for
some time.
Check chain tension frequently –
N
see chapter on "Operating
Instructions".
28

Fuel

This engine is certified to operate on
unleaded gasoline and STIHL two-
stroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of high-
quality gasoline and two-stroke air
cooled engine oil.
Use mid-grade unleaded gasoline with a
minimum octane rating of 89 (R+M/2)
and no more than 10% ethanol content.
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
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 HP Ultra 2-Cycle
Engine Oil since it is specially
formulated for use in STIHL 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,
chain saws, 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 container
from your vehicle and place the
container on the ground before filling. To
reduce the risk of sparks from static
discharge and resulting fire and/or
explosion, do not fill fuel containers that
are sitting in or on a vehicle or trailer.
The container should be kept tightly
closed in order to limit the amount of any
moisture that gets into the mixture.
The machine's fuel tank should be
cleaned as necessary.
Fuel mix ages
Only mix sufficient fuel for a few days
work, not to exceed 30 days of storage.
Store in approved fuel-containers only.
When mixing, pour oil into the container
first, and then add gasoline. Close the
container and shake it vigorously by
hand to ensure proper mixing of the oil
with the fuel.
Gaso - Oil (STIHL 50:1 or equiva -
line lent high-quality oils)
US gal. US fl.oz.
1 2.6
2 1/2 6.4
5 12.8
Dispose of empty mixing-oil containers
only at authorized disposal locations.
MS 661 C-M