●Unlessthepeakiscertainlyachieved,idleadjustmentwillbedifficultandnotstabilized.
●Startuptheengineandrunfor1minuteinrichcondition.Thenfullyopenthethrottle.
●ByturningthemainneedleCW,observingtachometerandexhaustsound,achievepeakcarefully.
●Operatethethrottletolowuntiltheenginerunsstablywithanidlespeedaround1,500rpmbyadjustingtheslow
needlewitha⊖screwdrivercarefully.
●Onceidlespeedisset,openthethrottletofullgradually.Ifthespeedbecomessloworgoesupsuddenly,adjustthe
slowneedlecarefullyuntilthespeedriseslinearlyfromidlingtopeakbyfine-tuning.
●Afterthatperformtheprocessfromidlingtopeakquickly.Ifthespeedrisesnon-linearly,finetunethemainneedle.
●Ifthespeedaroundslow-midrangegetscoughorhesitating,finetunetheslowneedleandchecktheresponseas
well.Repeatthisfine-tuningandresponsecheckcarefullyuntiltheresponseimproves.
●Carbadjustmentisaffectedbymanyfactorssuchasprop,flightstyle,humidity,temperature,atmosphere,oil,plug,
fuel,andsoon.Pleasekeeptryingtofindthebestconditiontomatchyourplane.
●Thebestrichnessoftheair-fuelmixtureatslowspeeddependsontheflightstyle.Generally,Scaleflightrequires
stabilityinlowspeedsoslightlyleanconditionispreferable.Acrobaticflightrequiresquickresponsefromlowthrough
high,soslightlyrichconditionispreferable.
●Tipforadjustmentoftheslowneedleistomakeitasleanastheenginedoesnʼtgetstolewhenopenthethrottlequickly.
●Tokeeptheenginelifelonger,adjustthemainneedleasrichaspossibleintherangeitdoesnʼtaffecttotherunning.
●Sinceoverthrottlingofthemainneedleleadstoknockingoroverheatandhasanadverseeffectontheconnecting
rodandcamgear,adjustalittlericherthanpeak.
●Onceyounoticeabnormalvibrationorsoundduringthrottlingthemainneedle,justreturntoopentheneedle
immediately.
●Wheretheplaneachievespeakcompletelyattheattitudeofascentshouldbeaproperpeakoftheengineduring
flight.
10.Tappetadjustment
●Aftercompletinggroundbreak-inoroperatingtheenginefor1hour,adjust
tappetgaps(valveclearances)byfollowingproceduretocompensateinitial
wearing,whiletheengineiscold.
●#1cylindershouldbeadjustedfirst,next#3,finally#2cylindershouldfollow
inorderbythesameprocedure.
●Removethesparkplugandrockercoversfromthe#1cylinder.
●Iftheattachedgauge(limitgauge,t=0.1mm)comestobeinserted,gaphas
beenenlargedbeyondtheallowablelimit.
●Turnthepropslowlyforwardbyhanduntiltherockerarmofintakestops.Furtherturntheproptobringthepistonto
theTDC(TopDeadCenter)ofcompressionstroke.
●Usetheattachedwrenchandhexagonalwrenchtoadjustthegapsindefinitelyclosetozero.
●Afteradjustment,putonthesparkplugandturnthepropforwardtocheckifthecompressionisenough.
●Ifthegapislowerthan0,thevalveisopenedallthetimesothecompressionisnotgenerated(then,loosenthescrew
toreset).
●Ifthegapiscorrectandcompressionisenough,securelytighten(butnotexcessively)thelocknut.
●Dothesameadjustmentforthe#3-#2cylindersinorder.
●ForSAITOengines,thetappetgapisenlargedduringoperationduetothermalexpansionofthecylinder(madeof
aluminum).Thereforesetthegapindefinitelyclosetozerowhentheengineiscold.
●Astappetgapisoneofthemostimportantfactorsinthemaintenanceof4-strokeengines,occasionallycheckit.
11.Other
●Duringoperation,thescrewsallovertheenginecanbeloosenbyheatexpansionofmetal.Sopleasetightenupthem
occasionally.
●Justafterstartuptheengine,performwarmuprunninginrichconditionforabout1minute,andjustbeforestoprun
itatidlingfor1minutetocooldownaswell.
●Whenstoptheengineafterthefinalflightoftheday,besuretostopbycuttingfueltoremovefuelfromthecarbure-
tor.Andremovethefuelfromthetankandreserveitwithspecialcare.
●Whentheexhaustvalvegetsdullbycarbonorsludgeespeciallyincoldatmosphere,removetherockercoverand
applysomeanti-rustspraytotheexhaustvalvetohelpthevalvetomovesmoothly.
●Neveruseanti-rustspraythatcontainsorganicsolventwhichdegradesrubbersealsinsidetheengine.
●Sometimestheoiloozesfromeachjointorcommissurehoweveritʼsnoproblemonperformance.
●Notesforpurchasingparts:Pleasegiveorderstotheshopyoupurchasedfromwith“Enginemodel”,“PartNo.orpart
name”,and“Quantity”.
Optionalparts
・Filterwithweight[G36-154] ・Rubbertubeforgasoline(1m)[G36-155]
・SparkplugSP-2[G60R3-120] ・Aluminumspinnernut[57T-30]
・Tappetadjustingkit[30-161] ・Digitaltachometer[G17-167]
Tappetadjustment
Fig.10
Mustnotbeinserted
(overgap)
Limitgauge
(0.1mm)
Closeto"0"withnolimit
-5-