Stihl MS 661 C-M, Instruction Manual

0000-GXX-2932-A0

► Push the hand guard away from the front han‐

dle with your left hand.

The hand guard engages with an audible click.

The chain brake is engaged.

7.2

Disengaging the Chain Brake

0000-GXX-2933-A0

► Pull the hand guard toward the front handle

with your left hand.

The hand guard engages with an audible click.

The chain brake is disengaged.

8

Mixing Fuel and Refueling

the Chainsaw

8.1

Mixing Fuel

This chainsaw requires a fuel mixture of gasoline

and two-stroke engine oil in a ratio of 50:1.
STIHL recommends you use STIHL MotoMix.
If you mix the fuel yourself, use only STIHL two-

stroke engine oil or another high-performance

engine oil in accordance with JASO FB, JASO

FC, JASO FD, ISO-L-EGB, ISO-L-EGC or ISO-L-

EGD.
STIHL specifies STIHL HP Ultra two-stroke

engine oil or an equivalent high-performance

engine oil in order to maintain emission limits

throughout the machine’s service life.

► Make sure that the octane number of the gas‐

oline is at least 90 RON and the ethanol con‐

tent is not more than 10%.

► Make sure the two-stroke engine oil you are

using meets the requirements.

► Depending on the required amount of fuel,

determine the correct amounts of two-stroke

engine oil and gasoline in a mix ratio of 50:1.

Examples for fuel mixes:

–

1 liter gasoline, 20 ml two-stroke engine oil

–

3 liters gasoline, 60 ml two-stroke engine oil

–

5 liters gasoline, 100 ml two-stroke engine

oil

► Pour two-stroke engine oil into a clean

approved fuel canister first and then add gaso‐

line.

► Thoroughly mix the fuel.

8.2

Fueling the Saw

► Shut off the engine and engage the chain

brake.

► Allow chainsaw to cool down.

► Place your chainsaw on a level surface so that

the fuel tank cap faces up.

► Use a damp cloth to clean the tank cap and

the area around it.

► Swing the grip on the fuel tank cap to the verti‐

cal position.

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WARNING

■ The chainsaw becomes hot during operation,

or in a very hot environment. Depending on

the type of fuel, altitude, ambient temperature

and the temperature of the saw, the fuel

expands and can cause a pressure build-up in

the tank. Fuel may escape as a spray and

ignite when the fuel tank cap is opened. This

can result in serious injuries and damage to

property.

► Allow the saw to cool down before opening

the tank cap.

► Open the tank cap slowly in stages.

► Turn the fuel tank cap about 1/8 of a turn

counterclockwise.

If the fuel tank is under pressure, you will hear

pressure being released.

► When the tank is no longer under pressure:

Turn the tank cap counterclockwise until the

marks on the cap and fuel tank are in align‐

ment.

8 Mixing Fuel and Refueling the Chainsaw

English

0458-759-0121-D. VA0.A21.

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