Stihl FC 75 - Engine; Muffler and Spark Arresting Screen Service; Crankcase Leakage Testing

Seemanual"Troubleshooting,
standardrepairs"fortrouble-
shootingprocedures.
Sparkarresterscreen
•
Removescrew(1).
•
Pulloutsparkarresterscreen(2).
-Cleansparkarresterscreen,fit
newscreenifnecessary.
Muffler
-Removeshroud,see3.1.
•
Removeouterscrew.
•
Removeinnerscrews.
-Liftoffmuffler.
•
Raisetongue(1)onretainer.
•
Pulloutseal(2).
Thepartsareinstalledinreverse
order.
-Presstonguedownagainafter
insertingseal.
-Tightenmufflerscrewstoa
torqueof9.5Nm.
-Refitshroud.
Defectiveoilsealsandgasketsor
cracksincastingscauseleaks.
Suchfaultsallowsupplementary
airtoentertheengineandthus
impairthefuel-airmixture.
Thismakesadjustmentofthe
specifiedidlespeeddifficult,ifnot
impossible.
Italsopreventsasmoothtransi-
tionfromidlespeedtopartorfull
throttle.
Thecrankcasecanbethoroughly
checkedforleakswiththecarbure-
torandcrankcasetesterandthe
vacuumpump.
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4. Engine
4.1 Muffler/sparkarresterscreen 4.2 Leakagetesting
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