Saito FG-21 User manual

Φ32.0mm 26.0mm 20.9cc
15”x8“~16”x6”
・Filterwithweight[G36-154] ・DurabletubeforGasoline(1m)[G36-155] ・Aluminumspinnernut[100-30]
・Tappetadjustingkit[30-161] ・Digitaltachometer[G17-167]
Bore Body:690g/Muffler:83g/Ignitionsystem:100g/Enginemount:156gStroke Disp.Weight(Approx.）
RPMRange Approx.2,000-9,500rpm Maxonground Approx.8,000-9,000rpm
Propeller SP-1orSP-2Plug
Optionalparts
4-strokeglow100-110classApplications
Batteryforignitionsystem
Specifications
FG-21InstructionManual
2.Ignition
●Ignitionarrangement-Placethemainunitasfarfromother
electricaldevicesaspossible.
(1)Plugcord（meshedhightensioncord)
Inserttheplugcapoftheplugcorddeeplyintotheplug
attachedtothecylindertomakesureitwillnotcomeoff.
(2)Sensorcord
Connectwiththecordfromthesensorattachedtotheengine.
(3)Batterycord(black/redcord)
Useafullychargedbatterythathasadequatespec.(6-12V,more
than1000mAisrecommended).Betweenthebatteryandmain
unit,makesuretosetaheavydutyswitchwhosecapacityis
higherthan3A.
(4)Tachometercord
Connectthedigitaltachometer(Option).Otherwisetheconnec-
torisnormallyvacant.
※
Standard
accessories
6.Tappetadjustment
ThevalveclearanceshouldbecheckedandadjustedafterBreak-inandeveryafter2hourswhiletheengineiscold.Beforeadjusting
tappetgaps,tightenthescrewsaroundcylinderetc.
1.Removethesparkplugand
rockerarmcoversfromthe
cylinder.Thenturntheprop
CCWbyhandtoplacethe
pistonatTDCofcompression
stroke.
2.Loosenthelocknutand
adjustthegapbyhexagonal
wrenchuntilyougetthe
correctgap(belowpic)for
bothofintake&exhaust.
3.Oncethegapisset,tighten
thelocknutandattachthe
plugandcovers.
4.Turnthepropbyhandto
checkifthecompressionis
enough.Ifthegapislessthan
0,thevalveisalwaysopened
sightlyandlosecompression.
Thenadjustagain.
CorrectGap
Mustnotbeinserted
Closeto“0”withnolimit
Limitgauge
(0.1mm)
Loosenthelocknut
Adjustthegapturning
thesetscrew
TopDeadCenter
（bothvalvesareclosed) Tightenthelocknut
tofixthesetscrew
・Enginemountset 1set ・Limitgauge(0.1t)fortappetadjustment 1pc ・Plugwrench  1pc
・Hexagonalwrench 1set ・Spannerfortappetadjustinglocknut 1pc ・Mufflerset  1set
・Ignitionsystem(w/sensor) 1set ・Sparkplug[SP-2](Attachedtotheengine) 1pc ・Anti-looseningnut 1pc
SwitchCapacity:3A〜
Sensor Battery
Voltage:6-12V
Capacity:1,000mA〜:
Plugcap
(2)Sensorcord
(Black)
(1)Plugcord
Mainunit
(3)BatteryCord
(Red/Black)
(4)Tachometercord
(Brown/Red/Orange)
FuelTank FuelLevel
ToOutsideoftheplane
Ventline
fuelsupplytocarburetor
Setthecenterofthecarb
slightlyabovethefuellevel
Fuelfillerline
Ventline
Gasoline-compatible
tankstopper
Gasoline-compatibletubing
Filterwithweight
Closeaspossible(within200mm)
Firewall
CCWtomake
rich
Main
Needle
Throttle
Fullopen
SAITOSEISAKUSHO,CO.,LTD. www.saito-mfg.com
22-7,3-chome,Tokagi,Ichikawa-shi,Chibaprefecture272-0024,JapanPhone:047-378-4156FAX:047-378-4155
Allspecificationsandmodelsaresubjecttochangewithoutnotice.
Note:
●Asitusesoil-mixedfuel,theplanemaysometimesgetdirtyfromtheexhaust.
●Useareliableandwell-balancedprop.Otherwiseitmaycauseanabnormalvibrationandcouldresultinaseriousaccident.
●Duringoperation,allenginescrewscanloosenduetometalheatexpansion.Checkandtightenoccasionally.
●Whentheexhaustvalvegetsdullbycarbonorsludgeespeciallyincoldatmosphere,removetherockercoverandapplysomeanti-rust
spraytotheexhaustvalvetohelpthevalvetomovesmoothly.
●Payattentiontothesurroundingssoasnottodisturbothersbynoiseandexhaust.
●Alwayskeepspectatorsstandbehindtheenginewhenoperatingtheengine.
●Asexhaustsmokeisharmful,becarefulnottobreatheinorotherwiseexposeyourselftoitsharmfuleffects.
●Payattentionnottotouchtherotatingpropellerwhenstartingengine,andmovetorearsideoftheaircraftoncetheengineisstarted.
●Allresponsibilitiesfortheuseoftheengine,andotherobligationsandresponsibilitiesbasedonlaws,regulations,etc.arebornebythe
purchaserandtheuser,andSAITOSEISAKUSHOCO.,LTD.isexemptfromanyresponsibilities.
Warranty:
●Ifthereisanydeficiencyfromthefactoryconcerningmanufacture,pleaseconsultwiththeshopordistributoryouboughtfrom.Our
companywillberesponsibleforrepair.However,anyfailureortroublecausedbyunnecessarydisassembly,modification,orotheruses
thanthoseprovidedintheinstructionmanualisnotsubjecttowarranty.
●Ignitionsystemissubjecttothewarrantyonlyforinitialfailure.Oncethesystemhasbeenactivatedsuccessfully,itwillnolongerbesubject
towarranty.
ver.March,2022
1.Fuel
●Thefuelismixtureofregulargasolineorhigh-octanegasolineandhigh-quality2-strokeengineoil.
●[Exampleofoilrecommendation]
・KlotzKL-200OriginalTechniplate・DeluxeMaterialsPowerModel2T-S・ENEOSRACINGSPECPRO-2T(SAITOSTANDARD)etc.
Ifsuchoilsarenotavailableinyourcountry,thenpleaseasktheofficialSAITOdistributorinyourcountryforanalternative. 
NEVERuse“cheapoil”designedforutilityenginesforbrushcutter,lawnmower,orchainsawetc.
●Besuretousethemixture“gasoline:oil=15~20:1”byvolumeratio.(Ex.1000mlofgasolineshouldbemixedwithmorethan50mlofoil).
●Duringthebreak-inprocess,use15:1mixedfueltoensurethebestlubricationforinitialrunning.
●Anydamagecausedbythefuelused,inwhichtheoilratioislowerthan20:1willnotbecoveredbywarranty.
●Donotusegasolinecontainingethanol.Itmaycausenotonlypowerlossbutalsocorrosioninsidetheengine.
3.Propeller
●RecommendedpropellerisAPC15x8~16x6whichbringsapprox.9,000rpm.Largersizeorgreaterpitchcancauseenginebrokendueto
overload.
●Useawell-balancedone.Neverusethepropellerthathasbeenscratchedordamagedevenifslightly.
●Asthepropelleriscompressedslightly,tightenthepropellernuteveryhourofoperation.
4.Break-inMOSTIMPORTANT!!
●Prop-recommendation:APC16”x6”.
●Use15:1fuel:oilratioforbreak-in.
●Nevermakethefuelmixtureleanduringbreak-in.Itcouldcauseseizureevenduringidlingor
low-speedrunning.
●Checkthattheslowneedleissettothereferenceposition.(Depth0.9~1.1mmfromthesurfaceof
thethrottlelever.)
●Beforestartingtheengine,openthemainneedleApprox.1+1/2turnsfromfullyclosed.
●Starttheengine(usingastarterisrecommendedforsafety).
●Soonafterstarting,Openthrottlegraduallyuptofull.InthemeantimeturnthemainneedleCCW.
ContinuetoturnthemainneedleCCWuntiltheRPMdeclines(toapprox4-5,000rpm)keeping
thethrottleopenedfully.
●Runinthisveryrichconditionfor1literoffuel.
●Now“initial”break-inisdone.
Slow High
Throttlelever
CCW→Rich
CC→Lean
Mainneedle
Slow(Idle)Needle
(Adjustwith⊖screwdriver)
CW→Lean
CCW→Rich
Approx.
0.9~1.1mm
SlowNeedle
5.Adjustmentofcarburetorafterinitialbreak-in.
◇Needlereferenceposition(Setafterinitialbreak-in)
●Starttheengineafteradjustingtheneedletothefollowingreferencevalue.
●Mainneedle：Approx.1+1/3~1+1/2turnsCCWfromfullyclosed
●Slowneedle：Approx.2+1/2~3turnsCW(Approx.0.9~1.1mm)fromthesurfaceofthethrottlelever.(Thenthrottlevalveshouldbefully
closed)
●Actually,thebestpositionoftheneedlesvarydependingontheprop,
temperature,humidityandsoon.Pleaseadjustasnecessaryafter
observingtheengineperformanceduringflight.
◇Peakadjustment
●Afterstartingtheengine,warmupforapprox.30secondsatlowspeed.
●Achievethepeakatfullthrottle.
→TurnthemainneedleCWgraduallytothepositionwheretheRPMis
greatest(thepeak).ContinuingtoturntheneedleCWpastthepeak
couldleadtoseizuresoturnitslowlyandcarefully.IftheRPMsudden-
lydecreasesafterpassingthepeak,instantlyreturnthemainneedle
CCWtoagainincreasetheRPM.Otherwiseitcoulddamagetheengine
seriously.
●OnceachievingpeakRPM,returnthethrottletolowspeed.Makeanoteofthepositionofmainneedleatthepeakatthattime.(Howmany
turnsyoudidCWbasedonthereferencevalue.)
◇SlowneedleAdjustment
●AfterachievingpeakRPM,nextisslowneedleadjustment.OpenthethrottlefromlowRPMtofullthrottlequickly.
●TurntheslowneedleCCWslightlyiftheenginehesitatesforamomentorstallsbeforetheenginereachesmaxRPMbecausethemixtureis
toolean.
●TurntheslowneedleCWslightlyiftheengineisslowtoreachpeakRPM(fullthrottleset)becausethemixtureistoorich.
●AdjusttheslowneedleasaboveuntiltheRPMfollowsthethrottlemovementsmoothly.Theimportantpointistoadjusttheslowneedle
AFTERthemainneedlehasbeenadjustedtoitspeak.
●Nowbreak-inatgroundlevelisdone.Adjusttappetsbythemethoddescribedlater.
◇Pre-flight/Flightadjustment
●Whentheslowneedleadjustmentisdone,checktheresponsebyrevvingupfromlowspeedtofullthrottlequicklyseveraltimes.
●OpenthethrottlefullyandturnthemainneedleCCWapprox.60〜90degreesfromthepeakposition.Thisistomakethefuelmixturericher
intheairwheretheRPMgethigherthanontheground.
●Afteralladjustmentsaremade,flyyouraircraftandfinetunetheengineaccordingtothesituation.Basicallytuningshouldbedonewiththe
mainneedle.Readjustmentoftheslowneedleisrarelyneededifthefirstadjustmentoftheslowneedlehasbeendonesuccessfully.
Voltage:6-12V,greaterthan1,000mA
※IfyouuseLi-Po,werecommendthespeclessthan2,500mAcapacityand
lessthan30Cdischargerate

SAITOFG-21PartsList
SAITOFG-21PartsList
No.
01
06
07
08
09
10
14
15
17
19
20
22
23
27
28
31
32
33
35
36A
37
38
39
40
41
42
43
Description
Cylinder
Piston
Pistonpin
Pistonpinretainer
Pistonring
Connectingrod
Cylinderscrewset
14-1,-2
Crankcase
Rearcover(Backplate)
Breathernipple
Frontballbearing
Rearballbearing
Crankshaft
Tpaercollet&Driveflange
27-1,-2
Propwasher&Nut
28-1,-2
Crankcasescrewset
31-1,-2,-3
Enginegasketset
32-1,-2,-3,-4,-5,-6,-8
Camgearhousing
Camgear
Camgearshaft
Steelwasherset
Tappet
Pushrod
Pushrodcover&Rubberseal
40-1,-2,-3
Rockerarm
Rockerarmscrew&Nut
42-1,-2
Rockerarmpin
Qʼty
1
1
1
2
1
1
1set
1
1
1
1
1
1
1ea.
1ea.
1set
1set
1
1
1
1set
2
2
2ea.
2
2ea.
2
No.
46
47
48
49
69
74
75
80
82-1
85
87
88B
89
90
91
95
110
152
153
160
Description
Valveset(In&Ex)
46-1,-2
Valvespring&Keeper&Retainer
47-1,-2,48
Valveretainer
Rockerarmcover
Intakepipe
Muffler
Mufflermanifoldset
75-1,80
Mufflernut
Carburetorcompete
82-1-1,-1-2,-1-3,-1-4,-1-5,-1-7,-1-8,-1-9,
-1-13,-1-14,-1-15,-1-16,-1-17,-1-18,-1-19,
-1-20,-1-21,-1-22,-1-23,-1-24,-1-25,-1-26,
-1-27,-1-28,32-5,85,88B,89,90-1,91-1
Fullthrottleneedle
Throttlebarrelassembly
82-1-5,-1-9,88B,89
Throttlelever
88B,90-1
Idleneedle
Carburetorscrew&springset
82-1-7,-1-8,-1-13,-1-16,-1-26,-1-28,90-1
Carburetorgasketset
32-4,-5,-6,82-1-9,-1-14,-1-18,-1-20,-1-22,-91-1
Enginemountset
95-1,-2,-3,-4,-5,-6
Antilooseningnut
Screw-pin(tofixdriveflange)
Electronicignitionsystem
153-1,-2,-3,-4,-5
Pumpassembly
82-1-17,-1-18,-1-19,-1-20,-1-21,-1-22,-1-23
-1-24,-1-25,-1-26
Qʼty
1set
2ea.
2
2
1
1
1set
2
1set
1
1set
1
1
1set
1set
1set
1
1
1set
1set
FG-21
Dimensional drawing
43.2
71.8
102.5
47.3
26.8 25.4
40 76 26.2
179
M8x1.25
40
52
60
63.5 25 13.7
34
4- Ø 4.2
31.5
22
50
50
66
66
17
33
4-Ø4.2
E.C.
E.C.
82-1
82-1
-27
88B
90-1
91-1
82-1
-8
82-1
-1
82-1
-15
82-1
-27
82-1
-5 82-1
-2
82-1
-16
89
82-1
-9
82-1
-7
85
90-1
82-1
-4
82-1
-3
82-1
-14
82-1
-28
32-5
82-1
-23
82-1
-25
82-1
-26
82-1
-20
82-1
-21
82-1
-19
82-1
-24
82-1
-18
82-1
-13
82-1
-25
82-1
-24
82-1
-17
82-1
-22