Craftsman 247.88755 Operator's Manual page 17

Checking Spark Pmug "
SparkPlug
DO NOTcheckfor sparkwith spark pBg removed.DO NOTcrank
enginewith sparkplug removed.
if the engine hasbeen running,the mufflerwill be very hoL Be careful
notto touch the muffler.
NOTE: Checkthe sparkplug oncea seasonor every 25 hoursof
operation.Changethe sparkplug oncea seasonor every 100hours.
Toensureproperengine operation,the sparkplug mustbe properly
gappedand freeof deposits.
1_ Removethespark plug bootand use a sparkplug wrenchto
removethe plug.See Figure13_
2_ Visuallyinspectthe spark plug.Discardthe spark plug if thereis
apparentwear,or if the insulatoris crackedor chipped.Cleanthe
sparkplug with a wirebrush if it is to be reuse&
3_ Measurethe plug gap with a feelergauge.Correctas necessary
by bendingsideelectrode.See Figure14_ The gap shouldbe set
to _02_03 inches(0_60@_80 mm).
4_ Checkthatthe sparkplug washeris in good conditionand thread
the sparkplug in by handto preventcross-threadi%
5_ After thespark plug is seated,tightenwith a spark plugwrenchto
compressthe washer.
NOTE:Wheninstallinga newsparkplug,tighten 1/2_turn after the
sparkplug seatsto compressthe washer.Whenreinstalling a used
sparkplug,tighten 1/8_to 1/4-turn after the sparkplug seatsto
compressthe washer.
The sparkplug mustbe tightenedsecurely.A loosesparkplug can
becomevery hotand can dama e the en ine.
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SparkPlugBoot
Figure13
Electrode
Figure14
17