Toro 303447 Operating instructions

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Program Study Workbook
To The Technician: The following Program Study Workbook is designed to enhance
your understanding of small engine operation and troubleshooting.
The format is designed to increase your comprehension of important concepts and
material that are addressed in the manual.
This Service Training material should also be utilized as future reference materials to be
used one your return back at your workplace.
If you still have questions or want further explanations/clarifications, talk with other
attendees here, and/or the Training Instructor for additional explanation or discussion.
Make the most productive use of your time in this program. The clearer the
understanding you have of the information provided the more effective you become to
your employer.
The Toro Company © 2012 The Toro Company
8111 Lyndale Ave South All Rights Reserved
Bloomington, MN 55068 U.S.A.
Printed in the U.S.A.

GoodafternoonandonbehalfoftheToroCompany,
thanksforattendingthisinformationalsessiononSmall
EngineTroubleshooting.
Ifthroughthecourseofthispresentation,youhaveany
questionspleasefeelfreetoask.
Thissessionisforyouandnooneshouldleavewithout
gettingtheirquestionsasked.
Smallenginesareanimportantcomponentofmanyof
themachinesthatareneededtomaintainturfareasand
performothermaintenancejobs.
Smallenginesareveryreliableandwithpropercareand
maintenancewilllastalongtime
However,whiletheyaredependablecomponents,when
theydonotperformasneeded,theycanbeoneofthe
mostfrustratingdevicesinourselectionoftoolsand
machines.

Themostcommoncomplaintaboutsmallenginesisthat
they“WONTSTART”
Thesecondmostcommoncomplaintisthatitruns,but
runspoorly.
Inthisprogramwewilldiscusswhatisneededforthese
enginestostart,whatisneededfromthemtorun
properlyandwhattestsandtroubleshootingstepscanbe
usedwheneitherofthesetwosituationsare
encountered.
Let'sexaminehowtoidentifytheproblemyoumayface
withasmallengine.
Ifyouhaveano‐startissueorapoorperformanceissue,
therearesomeFactsthatweneedtounderstandwhen
troubleshootingtheseengines.
WewilllookattheFACTS
F—Fuel
A–Air
C–Compression
T–Timing
S–Spark
Fortheenginetorunproperlyweneedtohave,Fuel,Air,
Compression,Timing&Spark.
Thesewillbediscussedinmoredepthlaterinthis
program.

Tobegin,weneedtoidentifytheenginetogetthecorrect
enginespecs,testingspecsandadjustmentinformation.
Theenginewillnormallyhavean“EngineIdentification”
numberontheengine.
Itmaybeontheenginehousing,onthevalvecoveroron
anenginesideplate.
Thesenumbersmayincludeamodel,type,andcode
BriggsandStrattonforexample,providethefollowing
informationthroughtheirnumberingsystem.
Modelprovidesengineconfigurationinformation.
Typelistspecificparts,paintcolor,OEMinformation.
Codeprovidesspecificmanufacturingdateandplant
information.

ThisisanexampleofabasicBriggs&Strattonenginenumber.
Model303447Type1234‐01Code01061201

A
Cubic Inch
Displacement
B
Basic Design
Series
C
Crankshaft, Carburetor,
Governor
D
PTO Bearing, Reduction Gear,
Auxiliary Drive, Lubrication
6
8
9
10
11
12
13
16
17
18
19
22
23
24
25
26
28
29
30
32
35
40
42
46
0-9
A-Z 0 - Horizontal Shaft, Diaphragm Carburetor, Pneumatic Governor
1 - Horizontal Shaft, Vacu-Jet
Carburetor, Pneumatic Governor
2 - Horizontal Shaft, Pulsa-Jet
Carburetor, Pneumatic or
Mechanical Governor
3 - Horizontal Shaft, Flo-Jet
Carburetor, Pneumatic Governor
4 - Horizontal Shaft, Vacu-Jet
Carburetor, Mechanical Governor
5 - Vertical Shaft, Vacu-Jet
Carburetor, Pneumatic or
Mechanical Governor
6 - Vertical Shaft
7 - Vertical Shaft, Flo-Jet
Carburetor, Pneumatic or
Mechanical Governor
8 - Vertical Shaft, Flo-Jet
Carburetor, Mechanical Governor
9 - Vertical Shaft, Pulsa-Jet
Carburetor, Pneumatic or
Mechanical Governor
0 - Plain Bearing / DU, Non-
Flange Mount
1 - Plain Bearing, Flange
Mounting
2 - Sleeve Bearing
Flange, Mounting, Splash Lube
3 - Ball Bearing, Flange
Mounting, Splash Lube
4 - Ball Bearing, Flange
Mounting, Pressure Lubrication
on Horizontal Shaft
5 - Plain Bearing, Gear Reduction
(6 to 1), CW Rotation, Flange
Mounting
6 - Plain Bearing, Gear Reduction
(6 to 1), CW Rotation, Flange
Mounting
7 - Plain Bearing, Pressure
Lubrication on Vertical Shaft
8 - Plain Bearing, Auxiliary Drive
(PTO) Perpendicular to
Crankshaft
9 - Plain Bearing, Auxiliary Drive
(PTO) Parallel to Crankshaft

Usingthepreviouschart,wecanseethatthe303447refertothefollowingenginespec.
30CubicInch,designseries3,horizontalcrankshaft,ballbearing,pressurelubricatedenginewithan
electricstartedandgeardrivealternator.
ThetypenumberlistspecificationnormallyrelatedtotheOEMoptionsandrequirement.
Thisincludedtheenginepaintcolor,governedspeedandOEMinformation.
Thecodetellsusthatthisenginewasbuilt,June12,2001online1,plant1.
Allofthisinformationisneededtoproperlytest,adjustandrepairtheengine.

FortheenginetorunthereareEight(8)eventsarerequiredfora2or4cycleenginetooperate.
First,Airisdrawnintothecylinder
Thecorrectamountoffuelismeteredintotheair
Theairandfuelaremixed
Theairfuelmixtureiscompressed
Thesparkplugfiresstartingcombustion
Combustioncausesarapidriseintemperature.Theincreasedtemperaturecausespressuretoincrease
whichproducesaforceonthepiston.
Theconnectingrodandcrankshaftconvertsthelinearmotiontorotarymotion.
Theburntgasesareexpelledfromtheengine.
Donotconfusetheseeventswiththefourstrokes(events)ofafourcycleengine.

Everyonehasheardofthefourstrokeorfourcycleengine.
Afour‐strokeengine,alsoknownasfour‐cycle,isaninternalcombustionengineinwhichthepiston
completesfourseparatestrokes—intake,compression,power,andexhaust—duringtwoseparate
revolutionsoftheengine'scrankshaft,andonesinglecombustioncycle.

INTAKEstroke:ontheintakeorinductionstrokeofthepiston,thepistondescendsfromthetopofthe
cylindertothebottomofthecylinder,reducingthepressureinsidethecylinder.Amixtureoffuelandair,
isforcedbyatmosphericpressureintothecylinderthroughtheintakeport.Theintakevalve(s)then
close.Thevolumeofair/fuelmixturethatisdrawnintothecylinder,relativetothevolumeofthe
cylinderiscalled,thevolumetricefficiencyoftheengine.
Detail
PistonmovesfromTDCtoBDC
Intakevalveopen
Exhaustvalveclosed
Pistonmovementcausesanareaoflowpressuretodevelopinthecombustionchamber.
Higherambientatmosphericpressureforcesairthroughtheintakesystem.
Ingascarburetedenginetheairpicksupthefuelasitpassesthroughthecarburetor.
Ingasfuelinjectedenginesthegasisaddedtotheairthroughaninjector.
InDieselenginesthefuelisinjectedintothecylinderattheendofthecompressionstroke.
180degreesofrotation
Anythingthatrestrictstheflowofairwillreduceengineperformance.

COMPRESSIONstroke:withbothintakeandexhaustvalvesclosed,thepistonreturnstothetopofthe
cylindercompressingtheair,orfuel‐airmixtureintothecombustionchamberofthecylinderhead.
Detail
PistonmovesfromBDCtoTDC
Intakevalveclosed
Exhaustvalveclosed
Pistonmovementreducesthevolumeofthecombustionchamber‐‐increasespressure.
Pressureofcompression=60to80psi.
Anypressurethatescapesreducestheperformanceoftheengine.
360degreesofrotation

Inorderfortheenginetorun,theairandfuelmixtureiscompressedinthecylinder.Thisincreasesthe
densityofthefuelairmixtureandallowsforamoreefficientcombustionprocess,andhigherpower
output.
CompressionratioisacomparisonbetweenthevolumeofthecylinderatBDCtothevolumeofthe
cylinderatTDC.
Ratiosof6to8:1arecommonforgasolineenginesand18to20:1forDieselengines.

POWERstroke:thisisthestartofthesecondrevolutionof
theengine.WhilethepistonisclosetoTop DeadCenter,
thecompressedair–fuelmixtureinagasolineengineis
ignited,usuallybyasparkplug,orfuelisinjectedintothe
dieselengine,whichignitesduetotheheatgeneratedin
theairduringthecompressionstroke.Theresulting
massivepressurefromthecombustionofthecompressed
fuel‐airmixtureforcesthepistonbackdowntoward
bottomdeadcenter.
Detail
PistonmovesfromTDCtoBDC
Intakevalveclosed
Exhaustvalveclosed
Rapidburningcausesrapidriseintemperature.
Rapidriseintemperaturecausesincreasedpressure.
Pressureinducesaforceonthepiston.
Forceonpistonproducestorqueoncrankshaft.
540degreesrotation
EXHAUSTstroke:duringtheexhauststroke,thepiston
onceagainreturnstotopdeadcenterwhiletheexhaust
valveisopen.Thisactionevacuatestheburntproductsof
combustionfromthecylinderbyexpellingthespentfuel‐
airmixtureoutthroughtheexhaustvalve(s).
Detail
PistonmovingfromBDCtoTDC.
Intakevalveclosed
Exhaustvalveopen
Wastegassesareexpelledfromthecylinder.
720degreesofrotation

Therearesomespecificcharacteristicsrelatedtoafour
cycleengine
Twocompleterevolutionsofthecrankshaftpercycle
resultsinapowerimpulseeveryotherrevolution.
Theseenginesaremorepopularthan2cycle
Theydorequiremorepartsthat2cycle.
Lessexhaustemissionsthan2cycle.
Typicallubricationsystemrestrictsangleofoperationdue
toeithersplashlubefromthesump,orpressure
lubricated,pullingoilfromthesump.
Theyarealsonormallymoredurablethan2cycle.

Inthe2strokecyclealleighteventsoccurintwostrokes,onerevolutionofthecrankshaft.

Thesparkplugfiresandthepistonmovesawayfromthecylinderhead.
Simultaneouslytheair‐fuel‐oilinthecrankcaseiscompressed.
Asthepistonreachesthebottomofthestroketheexhaustportisexposed.
Cylinderpressurecausesgassestoflowouttheport.
Furthermovementofthepistonandtheintakeportisexposed
Crankcasepressurecausesair‐fuel‐oiltoflowintothecombustionchamber.
Asthepistonmovestowardsthecylinderheadtheintakeandexhaustportsarecoveredandtheair‐fuel‐
oilchargeiscompressed.
Assoonastheintakeportiscovered,furtherpistonmovementcauseslowpressureinthecrankcaseand
anewchargefillsthecrankcase.

Therearesomespecificcharacteristicsrelatedtoatwo
cycleengine
Onerevolutionpercyclemeansapowerimpulseevery
revolution.
Fewerparts=lessweight
Usesscavengingtoexpelexhaustgases.
Higherfuelconsumption
Morenoise
Higheroperatingspeed
Higheroperatingtemperature
Greaterexhaustemissions
Smallsizeandweightforequalhorsepower.
Operateinmulti‐positions
Shorterexpectedlife
Earlierwementionsthe“FACTS”requiredforengine
operation.
Let'sexaminehowtoidentifytheproblemyoumayface
withasmallengine
ThiswillrequirealookattheFactsthatareneededto
maketheenginerun,andrunproperly.
Let'sbeginwithFuel.
WhenlookingatFUELthereareafewquestionstoask…
Doesithaveanyfuel?
Istheshutoffvalveclosed?
Isthefueldilutedwithwater?
AlcoholcontentofFuel?
Isthefuellineblocked?
Isthefueltankcapcloggedorunvented?
Isfuelinthecarburetor?

In recent years, small engines have run into issues
due to federally mandated changes in fuel
requirements.
This deals with the “Oxygenated” fuel that are
becoming more common in the country.
This started back in 1990 with the clean air act.
Clean Air Act 1990 requires gasoline to be modified
with oxygen additives in nonattainment zones.
Nonattainment zone: areas of the country that
exceed ozone levels.
There are Two common additives;
Alcohol
Methyl Tertiary Butyl Ether (MTBE)
Alcohol
Two types
Ethanol: distilled from grains and sugar containing
plants
Methanol: distilled from natural gas
The addition of alcohol to gasoline increases the
available oxygen during the combustion process.
Up to 10% ethanol acceptable for most small
engines.
Methanol is not normally recommended for small
engines.
MTBE
Removed from market because of health concerns.

Alcoholcontentcanplayamajorroleinperformanceissuesrelatedtosmallengines.
Theblendingofalcoholwithgasolinecaninsomeareasbeinconsistentwithalcoholcontentsometimes
beinghigherthanthedesired10%
Tocheckthealcoholcontestoffuel,thereareavarietyoftestdevicestoassistwiththis.
Thiskit,availablefromKohlerallowstheusertoquicklyandeffectivelytestfuelforalcoholcontent.
Tocheckalcoholcontent,addwatertothetester,uptothewaterline.
Thenaddgasolineuptotheneckofthetester.
Putonthecapandshake.
Thewaterwillmixwiththealcoholwhilethegasandthewaterwillremainseparated.
Setasideforacoupleminutesandthennotewherethewater/fuelseparationlineis.
Comparethatseparationlinetothelineonthetester.
Thiswillindicatethepercentageofalcoholinthefuel.
Ideallythisshouldbe10%.

Next,let'slookatAIR
Airisrequiredtoprovidetheoxygenneededfor
combustion,andtheenginealsoneedsasufficient
amountofair,forcompressiontobeadequate.
Insmallenginesthereareonlytwoareathatcanrestrict
theflowofairintotheengine.
Firstisthethrottleplateinthecarburetororintake
manifoldinfuelinjectedengines.

Theotherlocationistheairfilter.Thiscanbeanair
restrictionpointifnotproperlymaintained.
Theprimaryfunctionofanairfilteristodeliverbothhigh
airflowanddirtprotection.
Bothairflowanddirtprotectionarecriticaltoengine
performance.
Thebasictypesofairfiltersare.
Oiled‐foam,thisisafoamtypematerialwhichisoiledto
capturedirtparticlesandkeepsthemfromenteringthe
engine.
Thesetypesoffiltersarenormallycleanedandre‐oiledas
amaintenanceprocedure
Papertypefiltersusedapleatedpaperelementwith
holesofaspecificsizedesignedtocapturedirtparticles
alsoofaspecificsize.
Thesecanalsobecleanedasamaintenanceprocedure.
Dual‐elementfiltersareacombinationofbothtypes.
Theyconsistofapaperelementcoveredbyanoiled‐foam
element.

AirCleanerService–
Airfiltersshouldbecleanedpermanufactures
recommendations
Oiled‐Foamtypeelementscanbecleanedusingsoapand
water.Addasmallamountofoilandsqueezetosaturate
theelement.
Papertypeelementscanbecleanedbytappinggentlyon
aflatsurfaceorbyusingcompressedair.
Someenginemanufacturesmaynotrecommendusingcompressedairwhencleaningfilters.Ifyou
choosetoyoucompressedairtocleanapaperelementfilter,itisrecommendedthatthefilterbe
cleanedwithlowpressureair.
Thisreducesthelikelihoodthatthepaperelementisdamagedduringthecleaningprocess.
Arecommendationistoattachanairpressureregulatortothehosethatisusedforfiltercleaning.
Settingtheregulatorfor10‐20PSIwillnormallydoasufficientjobofcleaningwithoutriskingdamageto
theelement.
ThenextitemtolookatisCompression.