Engine Management; Adjusting The Carburetor; Spark Plug - Stihl FS 70 Instruction Manual

Engine Management

Exhaust emissions are controlled by the
design of the engine and components
(e.g. carburation, ignition, timing and
valve or port timing).
FS 70 R

Adjusting the Carburetor

The carburetor has been set at the
factory to provide an optimum fuel-air
mixture under most operating
conditions.
Adjusting Idle Speed
Engine stops while idling
Warm up the engine for about
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3 minutes.
Turn the idle speed screw (LA)
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slowly clockwise until the engine
runs smoothly – the cutting
attachment must not run.
Cutting attachment runs when engine is
idling
Turn the idle speed screw (LA)
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counterclockwise until the cutting
attachment stops moving and then
rotate the screw another 1/2 to 3/4
turn in the same direction.
WARNING
If the cutting attachment continues to run
when the engine is idling, have your
machine checked and repaired by your
servicing dealer.

Spark Plug

If the engine is down on power,
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difficult to start or runs poorly at idle
speed, first check the spark plug.
Fit a new spark plug after about 100
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operating hours – or sooner if the
electrodes are badly eroded. Install
only suppressed spark plugs of the
type approved by STIHL – see
"Specifications".
Removing the Spark Plug
Shut off the engine.
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1
2
Remove the spark plug boot (1).
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Unscrew the spark plug (2).
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