McCulloch MAC 291 User manual

//1MtrEULLOtrH,
t-OPERATION
MAINTENANCE
SAFETY
Yournewstringtrimmerisa complextool.
For your own safety, please read this
manualbeforeattemptingto operate
your
newunit. Failuretofollowinstructionscan
resultinserious
personal
injury. Spend
a
few moments
to familiarize
vourself
with
tew moments
to lamrlranze
yoursell
wrtn
your
trimmerbeforeeach
use.
USERMANUAL
MAC@291
6
EAGERBEAVER@28,282
GAsSTB'ruG TRIMMERS
PN
98587-04 OU.S.A.
. McCullochCorooration.
1993PrintedinU.S.A

Dear
Customer,
Thank
you
forpurchasing
a McCullo-ch
product'
With
proper
operation
and
mainienance
itwill
provide
you
with
yearsof
service,
ln order
to make
the best
useofyourinvestment'
be
CenfAtru
to
familiarize
yourself
with
the
contents
of
the
ENTIRE
User
Manual
before
attempting
tooperate
and
maintain
Your
unit.
Besure
tocarefully
follow
the
step-by-step
illustrations
inthis
manual
to start,
operate
and
maintain
yournew
product.
lnthe
manual
there
will
be
the
following
call-outs:
NOTE'
WARNING/CAUTION
and
WARRANTY'
A NOTE:
is used
to convey
additional
information'
to
highlight
a particular
explanation,
or expand
a step
description.
GENERALINFORMATION. . . . . 3
1-..|
.... Introduction
1-2.
... AboutYourManual
1-3.... AboutYourUnit
1-4.
... AssemblY
Requirements
1-5.
... Specifications
GENERALIDENTIFICATION. ...4
2-1
. ... General
ldentification
2-2. ... Sd{etY
Features
SAFEWPRECAUTIONS. . .. .. 5
3-1....
WhatToDo
3-2.... What
NOT
To
Do
ASSEMBLYINSTRUCTIONS ...7
4-1
. ... Handle
AssemblY
4-2. . .. SparkArrester
Installation
4-3. .. . DebrisShield
Installation
FUELANDLUBRICATION . .. ..8
5-1....
Fuel
5-2.
... Mixing
Fuel
5-3.
... FuelMixingTable
5-4.... Use
OfBlended
Fuels
OPERATINGINSTRUCTIONS ...9
6-1.
.. . StartingACold
Engine
6-2.
... To StoP
The
Engine
6-3... . WarmEngine
Start
A
WARNING
"..
CAUTION
ii"n1iti"" a procedure
which,
if not undertaken
or if
improperly
done,
can
result
in
serious
personal
iniury
or
damage
to
the
unit
and/or
both'
rn" @ (wARRANWsYMBoL)serves
notice
that
unless
instructions
or procedures
arefollowed'
any
J.t"gt l"rted will
voidthe
warranty
and
repairs
will
be
at
owner's
expense'
Service
other
than usermaintenance
should
be
o"rtormeO
bva McCulloch
Authorized
Service
Center'
b.t"g" or conditions
which
render
this product
inop"iiuru
caused
byimproper
maintenance
practices
will
void
the
manufacturer's
warranty'
McCulloch
CorPoratlon
Product
Servlce
DePartme
nt
TRIMMING
INSTRUCTIONS
. 11
7-1. ...Additional
Safety
Precautions
7-2. ... Stringhead
Line
Release
7-3. ...Trimming
Procedures
MAINTENANCE
INSTRUCTIONS 13
8-1. .. . Preventive
Maintenance
8-2. ... RePlacingCutterLine
8-3. ... Removing/
Replacing
Stringhead
8-4.
...AirFilter
8-5. .
.. FuelCaP/Fuel
Filter
8-6. ... CarburetorAdiustment
8-7....SParkPlug
8-8. ..
. SParkArresterScreen
8-9. ... Debris
Shield
Knife
Sharpening
8-10.
.. StoringAUnlt
8-11. .. Removing
AUnit
From
Storage
ACCESSORIES
&
LUBRICANTS
. .''''' 18
TROUBLESHOOTINGTHESTRINGHEAD
. . 19
TROUBLESHOOTINGTHE
ENGINE
. . . . .20

1-1.INTRODUCTION 1.3.
ABOUTYOURUNIT
YourMcCulloch
String
Trimmer
is a light,
portable,
hand-held
unit,
powered
by
a2-cycle
engine,that
runs
cooland
quiet.
Yourunitfeatures
a recoil
starterfor fast,consistent
startsand
a precision
diaphragm
carburetorfor
smooth
operation.
A spark
arrester
screen
thatmeets
all U.S.Forest
Service
Regulations
isfurnished
intheuserkit. For
additional
informationgoverning
useand
replacement
of
spark
arrester
screens
for your unit,see Safety
Precautions
andAccessories
and
Replacement
Parts
in
this
manual.
1-2.
ABOUTYOUR
MANUAL
McCulloch
unitsaredesigned
tomeetall
of
your
lawn
and
garden
trimming
needs. When
equippedwith
a
debrisshield
andstringhead,
your
unitcantrim
unsightly
weeds
andtall
grass
inthosehard
toreachareas
-along
fences,walls,foundations
andaround
trees.
1.4. ASSEMBLY REQUIREMENTS
Yourunit
willrequireassembly
of some
components
which
were packed separately
for shipping. Please
follow the directionsbeginning
in Section
4-1,
Assembly
Instructions.
NEVERoperate
your unit
withoutaproperly
installed
debrisshield.
Your User Manual
is both a reference
and a service
handbook that provides you with safety precautions,
easy-to-follow
assembly,
fuel, starting,
operating,
trimming
and
maintenance
instructions.
1.5. SPECIFICATIONS
Engine
Type Air-cooled
,2-Cycle,
Chrome
Cylinder
Displacement 29
cc
DryWeight... 9.9tbs.
Fuef
Capacity 24oz.
Drive
Shaft
Length 44"
Handle Delta
Cutting
Line O.O8O
or0.095"
Cutting
Swath 15u
Stringhead
. . . DuatLine
Semi-Automatic
Feed
Carburetor . primer/Diaphragm
Type
lgnition Electronic
Spark
Plug . Champion
DJ8JorEquivatent
Drive Direct

2.1. GENERAL
IDENTTFICATION
1. STRINGHEAD
2. CUTTER
LINE
3. DEBRIS
SHIELD
4. DRIVE
SHAFT
ASSEMBLY
5. HANDLE
6. THRoTTLETRIGGER
7. IGNITIoN
oN/oFF
SWIToH
8. cHoKE
LEVER
9. FAN
HoustNG
1
0. FUEL
TANK
11
, AIRFILTER
coVER
12, STARTER
HANDLE
13. MUFFLER
sHtELD
14. DRtvE
sHAFTRETAINtNG
scREw
15. SPARKARRESTER
SCREEN*
16. PRIMER
BULB
17. cRrP
\o
WARNING
CAUTION
Blades
CANNOT
beusedonthese
models. "Suppliedin UserKit
2-2. SAFEW
FEATURES
Numberspreceding thedescriptionscorrespond withnumbers above to help you locate thesafety feature.
3 DEBRIS
SHIELD
must
be
installed
toprevent
de-
ffi|rort spaytng
up
into
theoperator
and
prevent
thestring
from
extending
longer
than
necessary.
13 uurrlen Sgtrlo hetps
prevent
hands,
body
and/or
combustible
materials
from
making
contact
with
a hot
muffler.
15 Spnnx nnReSfER SCneEruretains
carbonand
otherflammable
particles
over0.023inches
insize
fromexhaust
flow.
NOTE: Compliancewith local,state and federal laws
and/or
regulations
governing
the useof a sparkarrester
screen is the user's responsibility.See Safety
Precautions
(Section
3) and MaintenanceInstructions
(Section
8)foradditionalinformation.
Theserial
number
ofyour
unit
islocated
onthe
engine.
Forhandy
reference
purposes,
you
may
want
to record
theserial
number
along
with
the
model
number.
Youmayalso
want
toetch
your
ownmarking.
MODELNUMBER SERIAL
NUMBER
PERSONAL
ETCHING:

3-1.WHAT
TODO
READ
YOUR
USEB
MANUALAND
ALL
SUP-
PLEMENTS
(tF ANY ENCLOSED)
THOR_
OUGHLY
BEFORE OPERATING
YOIJR
UNIT.
1. WEARCLOSE
FITTING,
TOUGH
WORKCLOTHING
thatwill
provide
protection,
such
as long
slacks
ortrou_
sers, safety work shoes, heavy duty work gloves, a
safety
face shield,
gogglesor safety
glasses
for eye
protection
and
a good
grade
ofear
plugs
orother
sound
barriers
br hearingprotection.
2. REFUEL
lNA SAFE
PLACE, Open fuet cap slowty
to
retease
any pressure
which may have formed in fuel
tank.To prevent
a fire hazard,
move at least 10 Jeet
(3meters)
lromfueling
area
before
starting.
3. lF
FUEL
HAS
SPTLLED
ON
UNIT,
be sure
engine
has
been
dried
completely
before
starting
it.
4, COMPLY WITH ALL FIRE PREVENTION
REGULATIONS.
Werecommend
you
keepashoveland
fire extinguisher
close by whenever
using
your unrt
in
areas
where
dry
grass,
leaves
or
other
flammable
mate_
rials
arepresent,
To operate
a gasoline-powered prod-
uct on U.S. National
Forest
Landsor forest,
brush
or
grass-covered
lands in many U.S. states - including
California,
Maine,
New
Hampshire,
Oregon,
Washington
- you must have an approved spark arrester screen
properly
installed
andmaintained
on
theengine
muffler.
Thespark
arrester
screen
must
remove
andretain
carb_
on and other
flammable
particles
over 0.023inches
in
size
fromengine
exhaust
flow.
NOTE: COMPLIANCE WITH ALL LocAL, STATE, oR
FEDERAL
LAWS
INTHE UNITED
STATES
ISTHE
USER'S
BESPONSIBILITY.
Your unit comes with a sparK
arresrer
screen
furnishe?
in
theuserkit.
Replacement
sparK
arrester
screen
kits are available
at your nearest
McCulloch
AuthorizedService Center listed under .SAWS, in vour
Telephone
Directory
Yellow
pages.
lf
you
have
any
questions
concerningspark arrester screens or their use, wrrte
to: McCullochCorporation,
product ServiceDepanment,
P.O.
Box
11990,
Tucson,
Arizona
85734.
Or,
vou
can
callour
toll-free
number,
USA: 1-800-423-6302.Arizona
residents
call
1-800-221
-6507.
NOTES:
8.
9.
5. TURN
UNITOFF
beforesetting
itdown.
6. ALWAYS
HOLDUNITFIRMLY
WITH
BOTHHANDS.
thethumband
fngersencircling
thehandles.
7. KEEPALLSCREWS
AND
FASTENERSTTGHT.
Never
operateyour
equipment
whenitisimproperly
adjusted
ornotcompletely
and
securely
assembled.
KEEPHANDLES
DRY, clean
andfree
offuelmixture.
KEEP STRINGHEAD
AS CLOSE TO GROUND
AS
PRACTICAL.
Avoid hitting smail objects with
stringhead. When cutting on a slope, stand below
stringhead.
NEVER
cutor trim
on a hill
or slope,
etc..if
thereis
theslightest
chance
ofslipping,
sliding
or
losing
firmfooting.
10. CHECK
AREA
YOU
WILLBE
TRIMMING
FOR
DEBRIS
that may be struck
or thrownduring
operation. Clear
areabefore
operating
equipment.
11. KEEPALL PARTS
OFYOUR
BODY
ANDCLOTHING
AWAY FROM
STRINGHEAD
when starting
or running
engine.
Before
starting
engine,
make sure stringhead
will
notcomeincontact
with
anyobstacle.
12. STOP
ENGINEbefore
examining
cutting
line.
13.
STORE EOUIPMENT
AWAY FROM POSSIBLE
IGNITION
SOURCES,
such
as
gas-powered
water
heat-
ers,
clothes
dryers,
or oil-fired
furnaces,
portable
heat-
ers,
etc.
14. ALWAYSKEEP
the debris
shield,
stringhead,
ano en-
gine
freeof
debris
build-up.
15. TURN
IGNITION
SWITCH
TO
OFF
and remove soarx
plug
boot
fromspark
plug
to avord
any chance
of acci-
dental
starting
before
replacing
stringhead
orline.
16. OPERATIONOFEOUTPMENT
should atwavs oe re-
stricted
to mature
andproperly
instructed
indviduals.

3SAFETYPRECAUTIONS 3
3.2. WHAT NOTTODO
WARNING
DONOT
OPERATETHISEOUIPMENT
withother
peo-
ple
oranimalsin
theimrnediatevicinity.
ALLOWa safe
distance
ofatleast30feet
(10
meters)
betweenoperator
andother
people
oranimals.
EDGINCJSCALPING
lSNOTRECOMMENDED
w he n
other
people
or
animalsarewithin100feet.
OONOTSWEEP
WITHUNIT.Sweepingrefers
totilting
head
attachment
tosweepawaydebrisfrom
sidewalks,
driveways,
etc.
tlfh oo NoT usE ANy orHER FUELthan that rec-
\llommended in
your
nnnual.
Alwaysfollowinstruc-
tions
intheFuel
andLubricationsection
ofthismanual.
Never
usegasoline
unlessit is properly
mixedwith
2-cycleenginelubricant.
Permanent
damagetoengine
willresult,voiding
manufacturer's
warranty.
5. DONOT
OPERATE
EQUIPMENTwearing loose
scarves,shorts,
dangling
jewelry,
keychains,
etc.,or
while
barefoot.
OONOTSMOKE
whilerefueling
or operating
equip-
ment.
DO
NOTSTART
EOUIPMENTWHEREYOU
FUELIT,
Move
at least10 feet (3 meters)
from fueling
areas
before
starting.
DONOT
OPERATE
UNITWITHOUTA MUFFLER
and
properly
installedmuffler
shield.
OONOTTOUCH
or letyourhandsor bodycomein
contactwith
a hotmlffler
orspark
plug
wire.
10.
11.
1. DO
NOTALLOWDIRT.
FUELORDEBRISto builduo
onengrne.
DO
NOTOPERATEUNIT
lNAWK\TVAROPOS|IIONS,
otfbalance,outstretched
arms,orone-handed.Always
usetwo hands
when
operatingunit
withthumbsand
fingersencirclingthe
handles.
DO NOTUSESTEELLINEOR PLASTIC-COATED
STEEL
LINE.The useof steel
line
or plastic-coated
steel
lineis extremely dangerous.Yourstringheadis
designed
tobe usedwith.080or.095"diameternylon
line.
DONOTRAISESTRINGHEAD
abovekneelevelwhile
unitisoperating.
lnjurytooperatorcouldresult.
DO NOTUSEANY TYPE BLADEOR SAW CHAIN
CUTTER
HEADunlesssoecifiedorincluded.
DONOT
USEUNITFORANYPURPOSESOTHER
thantrimming
ormowingweedsor
grass.
DONOTOPERATEUNIT
FORPROLONGEDPERIOOS,
Rest
periodically.
DO NOT
OPERATEUNITWHILEUNDERTHE
INFLUENCEOFALCOHOL
OR DRUGS.
DONOTOPERATEUN]TUNLESSDEBRISSHIELD
AND/ORGUARDIS INSTALLEDANDIN GOOO
CONDITION.
1fhoo Nor ADD, REMovE oR ALTERANY
\l/coupoNENTs oFTHts
pRooUCT.
Doing so
couldcause
personal
injuryand/ordamagethe unit
voidingthernanufacturer'swarranty.
12.
2.
3.
4.
13.
14.
15.
16.
17.
18.
19.
6.
7.
L
9.
CAUTION
Extremelylong
hairmaybe
drawnintotheenginebythecooling
fan.
Ensurelong
hairisprotected
andkeptclearofthecooling
fanintake
area.

4.1. HANDLE
ASSEMBLY
NOTE: The
Deltahandle
isattached
totheshaft
buthas
beenturned
under
forease
ofpacking.
Figure
z1-1A
1. Loosenadjustment
knobandrotate
handle
totopof
shaft.
(Figure
4-1A)
2. Retighten
adjustment
knob
securely.
4.2. SPARK
ARRESTER
INSTALLATION
NOTE: Spark Arrester
is required
when using your
trimmeron
U.S.National
Forest
Lands.Checkvourlocal
state
requirements.
1. Place your
uniton
aworkbench
orlevel
surface
with
themuffler
facingyouas shown
inFigure
4-2A.
2. Access
tothe
screen
areacan
bemade
through
the
opening
onthe back
ofthe muffler
shield. lt isnot
necessafo
to remove
the muffler
shieldto install
the
screen.
REMOVE
SCREW
Figure
4'2A
3. Using
a screwdriver,
remove
thescreen
cover
taining
screw.
(Figure
4-2A)
INSTALL
INORDER
SHOWN
>
:-@SCREEN
\K- \ -COVER
\
Figure
rl-2B -scREw
4. Install
the spark arrester
screen,the screencover
andscure in place
withthe retaining
screw.
(Figure
4-28)
NOTE: A dirtyspark arresterscreencan dramatically
reduce
performance.
4.3. DEBRIS
SHIELD
INSTALLATION
WARNING
Thedebris
shieldmust
beinstalled
toproperly
dispense
cutter
lineand
protect
operator.
@""Qg
Figure
zL3A
Figure
4-38
6-112"
To 8-112'
Figure
4-3C

5.1. FUEL
Enginefuelisamixtureof
gasoline
and2-cycleoil.The
correctratio
ofgasoline tooilisveryimportant.
Follow
theratiosintheFuelMixingTable.
Use regular
grade
unleaded
gasoline
mixedwith
McCulloch40:1
custom2-cycleengineoilfor best
results.Usemixino
ratiosinSection5-3.
CAUTION
@
Neveruse
straight
gasoline
in
your
unit.Neveruseafuel
mixturethathasbeenstoredforover
90days.
Thiswill
cause
permanent
enginedamage
and
voidthe
manufacturer'swarrantyfor
that
product.
CAUTION
@
lf 2-cycle lubricantother than McCullochCustom
Lubricant
is to be used,it must be a premium
grade
2-cycleoilmixed
ata
40:1ratio.lf
insufficientlubrication
is the cause of engine damage, it voids the
manufacturer's
warrantyforthat
product.
5-2. MIXINGFUEL
Mixfuelin
acontainerequippedwith
aflexiblespoutand
strainer.
SeetheFuelMixingTableforthe
correctratio
of
gasoline
tooil. Pourhalfof
the
gasoline
andallofthe
oil intothe container.Coverthe containerand shake
vigorously.
Addtherest
of
the
gasoline
andagainshake
containertothoroughlymixfueland
oil.
GAUTTON
@
Neverattempt
tomix
the
gasoline
andlubricating
oilin
the
fuel
tank
ofthe
unit.
Specialstarting
fluids
SHOULDNOT
beusedbecause
seals
andother
rubbercomposition
parts
maybe
damaged.
5.3. FUEL MIXING
TABLE
GASOLINE McCulloch
40:1RatioCustom Lubricant
1/2U.S.
Gal.
1U.S.Gal.
2.5US
Gal.
5 U.>.
(:at.
1.6oz.
3,2oz.
8.0
oz.
16.0oz.
48 ml (cc)
95 ml (cc)
237ml (cc)
475ml (cc)
1 Liter
5 Liters
20 Liters
0.9oz,
4.3oz.
17.Ooz.
25 ml (cc)
125ml (cc)
500ml (cc)
1lmp.Gal.
2lmp.
Gal,
5lmp.Gal.
4.3oz.
8.6
oz.
21.4oz.
125ml (cc)
250 ml (cc)
52s ml (cc)
Mixing
Procedute: 40 Part3 Gasoline to 1 Part Lubricant
1ml
=lcc
Ihe useofafueladditive
suchas STA-BILoGasStabilizer
or an equivalentwill
mrnimizethefornntionof fuel
gum
deposits.
Suchanadditive
shouldonlybeused
whenthe
fuel/oil
mixrs
prepared.
Add 11 ml
I0.4oz.
pergallon
of
gasoline
ormix
per
instructronsoncontainer.
NEVERadd
fuel
additivesdirectlyto
theunitfueltank.
5.4. USE
OFBLENDED
FUELS
Today'sfuels
areoftena blend
of
gasoline
andoneormoreoxygenatessuch
asethanol,methanol,
MTBE
(ether)
andaxonal.These
blendsareoftenreferredtoas
gasohol,premium
orsuperunleaded.
Werecommend
regularunleaded
gasoline
for
usein
your
McCulloch
product.
However,if
you
choosetousea
blended
fueloritsuseisunavoidable,
thefollowing
precautions
arerecommended.
1.Alwaysusefreshfuelmixed peryou
r
UserManual.
UsethespecialadditiveALCOHOL
PROTECiOR'o 1by
cold Eagle)or
equivalent
to inhibitconosionand
reduce
oiltfuelseparation
(mix as
directed).
Always agitatethe fuel mix before
fuelingunit.
Defuel
tankand runenginedry be-
forestonngthe unit.
PROBLEMSCOMMONTO
BLENDEDFUELS
Some
oroblems
associatedwithuseof
blended
fuels
include:
. Vaoorlock
. Poorwarmrestart
. Poor
performance
athighaltitudes
. Corrosronof fuel svstem
corDonentS
GASOHOLUSEMAYREQUIRE
CARBURETORADJUSTMENTS
YourMcOullochengine
islubricatedby
oil mixed
with
the fuel. Using
oxygenatedfuels
mayaltertheairlfuel
ratiocausingalean
mix
(lessfuel,
more
atr).
lf this
conditionis notcorrectedby
adjustingthe
carburetor,engine
darnagedueto poor
lubricationrnay
result.
YourMcCullochAuthorized
Service
Centercan makethese
adjustments.
a.

NOTE:lgnition
isalways
"ON"
6-1. STARTING
A COLD
ENGINE
NOTE: To minimize
load
onengine
during
starting
and
warm-up,
trim excess
cutter
lineto 5 inches.
(Figure
6-1A)
Your
unit
isdesigned
witha3 position
choke;
"CHOKE"
,'START'. and
"RUN".
Figure
6-18
TO START
ENGINE
1
. Move
choke
lever
to "CHOKE" position.
(Figure
6-18)
Figure
6-1C
2. Prime
the carburetor.
times.
(Figure
6-1C)
Figure
6-1D
3. Squeeze
thetrigger
totheFULLTHROTTLE
position.
(Figure
6-1
D)
Figure
6-1E
4. Pull
starterrope
outa short
way until
resistance
is
lelt (approx.
4 inches). Pullstarter
ropebriskly
4
times. A smoothrapid
pull
isrequired
fora strong
spark.
(Figure
6-1E)
NOTE: Throttle
must
remain
in
fullthrottleposition
until
engine
starts
and
warms
up(approx.
1
0 seconds).
5. Move
choke
lever
to "START" position.
pull
starter
rope
again
4 tirnes
whileholding
trigger
at thefull
throttleposition.
(Figure
6-1F)
6. lfengine
fails
tostart,
repeat
steps
1through
5.
PRIMER
t-{
Pump
theprimer
bulb
10

a
6OPERATI
NGINSTRUCTIONS 6
6-2. TOSTOP
THE
ENGINE
NormalStopping:
Flgure
61G
7. Onceengineslarts,leavethechokeinthe"START"
position
for10seconds,thenmove
choketo "RUN"
position.
(Figure-6-1
G)
NOTE: Yourunitis equipped
witha throttleadvance
whichalsocanbe
usedduringstarting.
(Figure
6-1H)
NOTE: lfenginefails
tostart,afterrepeated
attempts,
refertoTroubleshooting
section.
NOTE: Always
pullstarter
ropestraightup. Pulling
starterat an anglewillcauserope
to rubagainstthe
eyelet. Thisfrictionwillcauseropeto frayandwear
quickly.
Always
holdstarterhandlewhen
roperetracts.
Neverlet
ropesnapbackfrom
extended
position.
This
could
causeropeto snagorfray
andalsodamage
the
starterassembly.
Figure 6-2A
1. Releasethrottle
trigger. Letengine
returnto idle.
Extend
staderrope4"-6"
to absorbstrainon starter
components
when engine stops. Push and hold
ignitionstopswitchuntilenginestops.
Allowstarter
ropeto retractslowly.
(Figure
6-2A)
6.3,WARMENGINE
START
Flgure6-3A
1. Placechoke
in
"START"
position.
(Figure
6-3A)
2. Graspthrottle
handlefirmly,squeezethrottletrigger
toFULL
throttle
position.
3. Pull starter
ropebrisklyuntilengine
starts,butno
more
than6times. Keepthrottle
atFULL
position
until
enginerunssmoothly.
4. lfengine doesn'tstart,
place
choke
in
"RUN" posi-
tionand
pull
starter
rope5moretimes.lfengine
still
doesnotstart
itis
probably
flooded.
Wait
5minutes
andrepeat
procedure
withchokein
"RUN" position
andthrottlefullopen.
t0

7-1.
ADDITIONAL
SAFEW
PRECAUTIONS
Before
operating
your
unit,review
ALLSAFETY
PRE)AUT\oNSinthismanual.
WARNING
CAUTION
lF UNFAMILIAR
WITHTRIMMING/CUTTING
tech-
niques,
practice
the procedures
with ENGINE
in
'OFF'position.
ALWAYS
CLEAR
WORK
area
ofdebris
suchas
cans,
bottles,
rocks,
etc.Striking
objects
cancause
serious
injury
to operator
or bystanders
and alsodamage
equipment.
lfan
objectisaccidentally
hit,immediately
TURNENGINE
OFFandexamine
equipment.
lf
stringhead
is crackedor broken,
or plastic
debris
shield
isdamaged,
replace
those
parts
immediately.
Neveroperate
unitwithdamaged
ordefective
equip-
ment.
ALWAYS
HOLD
UNITFIRMLY
with both hands.
thumbs
and
fingers
encircling
handles.
ALWAYS
WEAR
PROPER
CLOTHING,
work shoes,
work gloves,
safety
goggles
and ear protection
to
guard
against
hearing
impairment,
ALWAYS
TRIM
ORCUTAT
HIGH
ENGINE
SPEEDS.
Donotrun
engine
slowlyatstart
orduring
trimming
operations.
DONOTuse equipmentfor purposesotherthan
trimming
ormowingweeds.
NEVER
raisestringheadabovekneeheight
during
operation.
DONOToperateunitwithother
people
oranimalsin
theimmediatevicinity.Allow
a minimumof30feet
betweenoperatorandother
people
andanimalswhen
trimmingor mowing. Allowa distance
of 100feet
between
operatorandother
people
and
animalswhen
EDGINGorSCALPINGwith
stringhead.
NEVER
OPERATEEQUIPMENT
if takingmedication
that
produces
drowsinessorreducesreflexes.
NEVEROPERATEEQUIPMENT
while
drinkingalco-
holicbeverages
orwhileundertheinfluence
ofalcohol
ordrugs.
lFOPERATING
UNITONA SLOPE,
standbelow
the
cuttingattachment.
DONOTOPERATE
ona siope
orhillyincline
ifthereistheslightest
chanceofslipping
orlosing
your
footing.
7-2.
STRINGHEAD
LINE
RELEASE CAUTION
Periodically
removeweedwrapto prevent
overheating
the
drive shaft. Weed wrap occurs when strands of weeds
become entangledaround the shaft beneaththe debris
shield
(Figure
7-28). Remove
weedwrap
withascrewdriver
or
similardevice,
orrefertoSection
8-3,Removing
/ Replac-
ingStringhead.
Figure
7-2A
NOTE: The
bump-and-feed
stringhead
allowsfor
quick
and
easy
linefeeding
withoutthe
needtostop
engineto
advance
line.
(Figure
7-2A)
WARNING
CAUTION
DONOT
usesteel
wireor
plastic-coated
steelwire.
To release
fresh
line,run engineat fullthrottleand
"bump"
stringhead
against
lawn.
Linewillautomatically Fiqure
7-28
release.
The
knifein
debrisshield
willtrimexcessline. ' 'Y-'-
11

7TRIMMING INSTRUCTIONS 7
7.3. TRIMMINGPROCEDURES
When properly equippedwith a debrisshieldand
stringhead,
your
unitwill
trim
unsightlyweedsandtall
grass
inthosehard-to-reach
areas
-alongfences,walls,
foundationsand
aroundtrees. lt canalsobeused
for
edging
alongwalkways
anddriveways.
Anditcanbe
usedfor scalpingto removevegetationdownto the
ground
foreasier
preparation
ofagarden
ortocleanout
a particular
area.
WARNING
Donotusesteelwireor
plastic-coated
steelwireofany
kindwith
your
stringhead.Seriousoperatorinjurycan
result.
NOTE: Evenwithcare,trimmingaroundfoundations,
brickor stonewalls,
curves,etc.,willresultin above
normalstringwear. To release
freshline,see
instructionsinSection7-2,
StringheadLineRelease.
TRIMMING/MOWING
Swingtrimmer
witha
sickle-likemotionfrom
sidetoside.Donottilt
the stringheadduring
the procedure. Test
areato betrimmedfor
proper
cuttingheight
Keep stringheadat
same levelfor even
depthofcut.
CLOSEBTBIMMING
Positiontrimmerstraightaheadwithaslighttiltsobottom
ofstringhead
isabove
ground
andstringcontactoccurs
at
proper
cutting
point.
Alwayscutawayfromoperator.
Donot
pull
trimmerintowardoperator.
FENCE,trOUNDATION TRIMMING
Approach
trimmingaroundchainlinkfences,
picket
fences,rockwallsandfoundationsslowlyto cutclose
withoutwhippingstringagainst
the
barrier.lfthestring
comesincontactwithrock,
brickwalls,orfoundations,it
willbreakorfray.lf string
snagsfencing,itwillsnapoff.
TRIMMINGAROUND
TREES
Trimaround
treetrunkswitha slowapproachsostring
doesnotcontact
thetreebark. Walkaroundthetree
trimming
fromlefttoright.Approach
grass
orweedswith
tipofstringandtiltstringheadslightlyforward.
WARNING
Use extreme
caution
when EDGING
or SCALPING.
Keep
a distance
of 100feetbetween
operator,
other
people
andanimals
duringthese
operations.
EDGING
Tiltunitto
theleft
sothat
stringhead
is
inavertical
position.
Thiswillallow
the nylonline
to sklm
along
the edge
of the
concrete. Before
edging,
you
may
wantto
adjust
the handle
so as
tomake
thisoperation
as
effortless
as possible.
Always
keepa distance
of 100feet
fromother
people
and
animals
whenedging.Do
notattemptthis
procedure
ifthere
isanychance
flyingdebris
couldinjure
operator,
other
people
orcause
damageto
property.
SCALPING
Scalping
referslo
removal of all
vegetationdown
tothe
ground.
Todo
this,tilt
thestringhead
toabout
a 30 degree
angleto
the left. By adjusting
the handle
you
will
havebetter
control
during
thisoperation.
Always keep a
distanceof 100feet
fromother
people
and
animals when
scalping.
Donotattempt
this
procedure
ifthereisany
chance
flyingdebris
couldinjure
operator,other
people
orcause
damage
toproperty.
WARNING
DONOT
SWEEP
WITHTRIMMER
Sweeping
refersto tilting
stringheadto sweep
away
debris
fromwalkways,
etc. Your
trimmerisa powerful
tooland
smallstones
orothersuch
debrismay
be
hurled
50 feetor more,
causinginjury
or damageto nearby
property
such
asautomobiles,
homesand
windows.
12

8.1. PREVENTIVE
MAINTENANCE
Service
otherthan routine
user maintenance
items
should
be performed
by your McCulloch
Authorized
Service
Centerlisted
in under
"SAWS"
in the Yellow
Pages
of
your
telephone
directory.
Keep
your
unit
clean. Donotallow
filters,mufffer
and
cylinder
finsto become
plugged
orcoveredwith
dirtor
debris.
fi[ Neveruse
dirtyfuel
ordirty
oil. Engine
damage
\lf couldresult.
Always
follow
instructions
intheFuel
and
Lubrication
section
ofthismanual.
Agoodpreventive maintenance
program
will
prolong
the
lifeandmaintainthe
performance
of
your
McOullochunit.
After
thefirst7daysor15hoursofoperation,
whichever
comes
eadiest,take
your
unitto
your
McOulloch
Author-
ized ServiceCenterfor an inspectionand check-up.
Your
dealerwillbe
pleased
tohelp
you
setupa preven-
tivemaintenance
program
tosuit
your
needs.
Therec-
ommendedfirst7-dayor 1S-hour
check-ups
and a
follow-up
ofregular
periodic
check-ups
andtune-ups
will
assurelong,satisfactory
servicefrom your McCulloch
product.
Thisservicewill
be
performed
at
your
McCul-
lochAuthorized
ServiceCenteratexisting
servicerates.
MAINTENANCE
CHECKLIST
NOTE: The
maintenance
checklist
below
isa guide
for
preventive
maintenance.
Cleaning,adjustment,
and
parts
replacement
may,
under
certain
conditions,
berequired
atmore
frequentintervalsthan
thoseindicated.
MAINTENANCE
CHECK
LIST 5
H
o
U
R
S
20
H
o
U
R
S
lil
r
I
ITEM ACTION
SCREWS
/ NUTS /BOLTS INSPECT
/TIGHTEN
CONTROLS INSPECT
TFEPLACE
ASFEQUIFED
AIRFILTER CLEAN
ORREPLACE
FUELFILTEB REPLACE
DEBRIS
SHIELD INSPECT
REPLACEAS
REQUIRED
STRINGHEAD INSPECT
REPLACEAS
REQUIRED
SPARKPLUG CLEAN/ADJUST/FEPLACE
MUFFLER TCLEAN
LAMINATION
GAP *CLEANTADJUST
EXHAUST
PORTS *CLEAN a
SPARKARFESTER
SCBEEN INSPECT
REPLACE
CYLINDEB
FINS TCLEAN
CARBUFETOR .CLEAN
STARTER
ROPE INSPECT a
*REPLACE
ASREOUIRED
DRIVE
SHAFT TLUBRICATE
(Every
50
Hours) a
FUEL
HOSES INSPECT a
*REPLACEAS
REOUIRED
tFlecommended
forMaintenance
bya McCulloch
Authorized
ServiceCenterTechnician
13

8MAI
NTENANCE
INSTRUCTIONS I
8.2. REPI.ACINGCUTTERLINE
Figure8-2A
1. TurntheknobCOUNTERCLOCKWISE
andremove
it. lfrequiredusestringheadwrench.
2. Removethespoolandspring.
3. Remove
anyremainingcutterline.
(Figure
8-2A)
Figure
8-2D
6. Lockeach
end
intoa slotonopposite
sides
ofthe
spool. Install
the spring
overthe spindle. Insert
eachend
ofthe
linethroughan
eyeletinthehousing
andlower
thespool
intothe
housingwhilefeeding
the
linethrough
theeyelets.Ensure
thespringseats
itselfinto
thespool.
(Figure
8-2D)
HAND
TIGHT
ONLYDO NOT
USE
WRENCH
Figure
8-2E
7. Oncethespool
is inplace, apply
pressure
onthe
spoolcompressing
thespring.Pull
eachendofthe
linesharplyto
unlockthem
fromtheslots.Continue
toapply
pressure
tothespool
untiltheknobcanbe
threaded
CLOCIQVISE
ontothe spindle.Tighten
the
knobsecurely
byhand
only.DONOTUSETHE
STRINGHEAD
WRENCH
TOT]GHTEN.
(Figure
8-2E)
NOTE:
Apply
an anti-seize
compound
(Permatex@
'133A
Anti-seize
orequivalent)to
thethreadstomakethe
knob
easierloremovenexttime
service
is
required.
Flgure
8-2F
8. Trimthe
excess
linetoapproximately
5inches. This
will minimize
loadon engine
duringstarlingand
warm-up.
(Figure8-2F)
4. Doublea 18ft.lengthof .095
(or.OB0)cufterline.
Threadeachendthrough
oneofthetwosetsofholes
on the top of the spool. Pullbothendsevenly
throughtheholes.
(Figure
B-28)
Figure8-2C
5. Wind both ends aroundthe spool togetherin a
CLOCKWISE
directiontowithin6"oftheends.DO
NOT
TWISTUNEONSPOOL.Twistingline
could
causestringheadtofeedimproperly.
(Figure
8-2C)
14

8-3. REMOVING
/ REPI-ACING
STRINGHEAD
IMAINTENANCE
INSTRUCTIONS 8
Figure&3A
1. Turntheknob
COUNTERCLOCKWISE
toremove.
Usethestringhead
wrenchifrequired.
2. Removethespool
andspringfrom
thehousing.
3. Removethe
housing.Gently
tapbackofhousing
to
loosen.(Figure
8-3A)
_? o*
Figure
8-48
2. LiftfilterfromAir
Box.
(Figure
8-4B)
3. Washfilterinsoap
andwater.DONOTUSE
GASOLINEI
4. Airdryfilter.
5. Reinstallfilter
in
reverse
orderofremoval.
NOTE: Replaceflteriffrayed,
torn,
damagedor
unabletoclean.
8.5. FUELCAP/FUELFILTER
CAUTION
Removefuelfromunitandstoreinapprovedcontainer
beforestartingthis
procedure.
FUEL.AP
\ t--<
htu
Figure8-5A
NOTE: Keepventonfuelcapcleanofdebris.
(Figure
B-5A)
1. Liftfuellineoutoftank.Steelwirewithhookorpaper
clipworkswell.
(Figure
8-5B)
HAND
TlGHT
ONLY
OONOT
USE
STRINGHEAO
WRENCH
Figure8-3B
4. Remove
thereplacement
stringhead
fromthe
pack-
age
intact.Place
itonthespindle.
Ensurethe
hex
on
thespindleis
wellseated
intothehousing.
5. Compress
the'spoolinto
thehousing
andthread
the
knob
intotheassembly.
Tighten
theknob
CLOCK-
WISE,
BYHAND
ONLY.
(Figure
8-38)
84. AIRFILTER
ToCleanAirFilter:
AIR
FILTER AIRFILTER
COVER
COVERSCREWS
Figure8-4A
1. Remove
2screwsholding
airfiltercover
remove
cover.
(Figure
8-4A)
15
FUEt
FILTER
in
place
and

8MAI
NTENANCE
INSTRUCTIONS I
Figure&5C
2. Pull offwithatwistingmotion.
(Figure
8-5C)
3. Replacefuelfilter.
NOTE: Neveroperatethetrimmerwithoutthe
filter.Internalenginedamagecouldresult!
CARBURETORADJUSTMENT
The carburetorwas pre-set at the factoryfor optimum
performance. lf further adjustmentsare necessary,
please
take
your
unittothenearestMcOullochAuthor-
izedServiceCenterlistedintheYellowPages.
8-7. SPARKPLUG
CENTER
ELECTRODE
SIDE
ELECTRODE
Figure
8-7B
4. Adjust
gap
to
.025in.Bend
sideelectrode
onlyusing
agapping
tool.
(Figure
8-78)
5. Reinstall
spark
plug
andtorque
to 105to 130inch
pounds.
Reconnect
spark
plug
boot.
8€. SPARK
ARRESTER
SCREEN
NOTE: lt is notnecessary
to take muffler
shieldoffto
replace
orinstall
a newspark
arrester
screen.
@
8-6.
fuel
SPARKPLUG
BOOT
Figure8-7A
1. Removespark
plug
bootwith
a
twistand
pull
motion.
(Figure
8-7A)
2. Removethespark
plug.
3. Cleanspark
plug
electrodeswith
emery
cloth.
REMOVE
SCREW
Figure
8-8A
SCREEN
Flgure&88
1, Toreplacespark
arrester
screen,remove
theretain-
ing screw
and screen
cover. Discard
old screen.
Install
newscreen.
(Figure
8-8A
&8-88)
16

8MAI
NTENANCE
INSTRUCTIONS I
8.9. DEBRIS
SHIELD
KNIFE
SHARPENING
1. Remove
cutter
knifefrom
debris
shield.
2. Place
knife
ina bench
vise. Sharpen
knifeusing
a
flatfile,
being
careful
tomaintain
theangle
ofcutting
edge.Fileinone
direction
only.
Figure8-10A
B. Pour1 teaspoonof clean2-cycle
oil into
thecom-
bustion
chamber. Pullstarter
ropeslowly
several
timesto coatinternal
components.
Replace
spark
plug.
(Figure
8-10A)
9. Storeunitinacool,dryplace
away
fromany
source
ofignition
suchasanoil
burner,water
heater,
etc.
8.11. REMOVING
A UNITFROM
STORAGE
Figure
8-9A
3. Reinstall
knife.
Tighten
fasteners
securely.
(Figure
B-9A)
8.10.
STORING
A UNIT Clean
and
gap
spark
plug
orinstall
anewspark
plug
with
proper
gap.
Prepare
unitforoperation.
Fillfueltank
with
proper
fuel/oil
mixture.
SeeFuel
and
Lubrication
Section.
1. Removespark plug.
2. Pullstarter
ropebriskly
to clearexcess
oil from
combustion
chamber.
3.
fi[Failure to
follow
these
steps
maycause
varnish
to
\l/form inthe carburetor,
difficult
starting
or perma-
nent
damage
after
storage.
1. Perform
allthd
general
maintenance
recommended
in
theMaintenance
Section
of
your
User
Manual.
2. Clean
exterior
ofengine,
drive
shaft
assembly,
de-
bris
shield
andstringhead.
3. Drain
fuelfrom
the
fueltank.
4. Afterfuel
isdrained,
start
engine.
5. Runengine
atidle
untilunit
stops.This
will
purge
the
carburetor
offuel.
6. Allow
engine
to
cool
(approximately
5 minutes),
7. Using
aspark
plug
wrench,
remove
thespark
plug.
4.
5.
l7

FOR PERFOBMANCEANDSAFETYREASOA'S
USEONLYGENUINE
McCULLOCH ACCESSORIESANDBEPIACEMENT PABTS.
DESCRIPTION
ACCESSORIESandREPLACEMENTPARTS
PART
NUMBER
Dual
UneStringheadAssembly. .
DualLine-on-Spool
BumpKnob
300160
3001s9
300339
3003s6
21904341
300323
22397541
224040
21698s
BumpSpring
Spark
PlugDJSJ
Air Filter
Debris
Shield
SparkArrester
Screen
FuelFilter
LUBRICANTS
3.2oz.ONE
SHOT 22325141
224477
98463
8oz.
(for
2.5
gal.
mix)
16oz.
(with
easy
mixchamber)
18

PROBLEM PROBABLE
CAUSE
Linewon't
feed.
Line
is
tangled
inside
stringhead. Remove spool from unit;
disassemble.
Untangle
line
and
windcorrectly
in
direction
indicated
onspool
(see
Section
8).
Upon
removing
spool,
line
appears
tobemelted
together. Trimoffdamaged
line
andrewind
line(see
Section
B).
Line
wound
in wrong
direction
inside
stringhead.
Remove
spool. Check
to be
certain
lineis wound
in direction
indicated
on lineelement.
(see
Section
8)
Insufficient
line
inside
stringhead. Remove
spool
and
install
new
line
(see
Section
B).
Internal
damage
to stringhead
caused
bybumping
head
too
hard
on
ground
while
advancing
line.
Disassemble
stringhead
and
examine parts for damage.
Replace
parts
orentire
head
(See
Section
8).
Line
snaps
off
orfrays. lmproper
trimmingprocedures,
or
poor
quality
line. SeeGeneral
Trimming
Instructions
orreplace
line(see
S6ction
B).
Unable
toremove
stringhead
knob.
Stringhead
and
shaft
are
hot
tothe
touch.
Stringhead
knob
over
tightened
-
use
stringhead
wrench
suppliedin
user
kit.
U
se anf,i-se
ize com pou
nd
(Permatexw
133A Anti-sdize
or
equivalent)
and reinstall
knob
HAND
TIGHT
ONLY.
Weed
wrap. Remove
weed wrap (see
Section
7).
l9

PROBLEM PROBABLE
CAUSE CORRECTIVE
ACTION
Unitwon'tstartor starts
butwillnot
run. I
ncorrect
starti
ngProcedures Follow
instructions
in the User
Manual
(See
Section
6).
lncorrect carburetor mixture
adjustment
setting Have carburetor
adiusted
bY an
Authorized
Service
Center.
Fouled
spark
plug Remove,
clean
and
gaP(orrePlace)
spark
plug. lf plugis wet,reinstall
plug
and
holdat
full
throttle
until
unit
starts.
lfplug
isdry,
try
starting
with
choke
on(See
Section
8).
Fuelfilter
plugged Replace
fuelfilter
(SeeSection
B)'
Unit
starts,
butengine
has
low
power.Incorrect
lever
position
on
choke Move
toRUN
position.
Dirty
spark
arrestor
screen Replace
spark
arrester
screen.
Dirty
air
filter Remove,
clean
and
reinstall
filter.
lncorrect carburetor mixture
adjustment
setting Have carburetor
adiusted
bY
Authorized
Service
Center. an
Engine
hesitates lncorrect carburetor mixture
adjustment
setting Have carburetor
adjusted
bY an
Authorized
Service
Center.
No
power
under
load
Runserratically Incorrectly
gapped
spark
Plug Clean
/ gap
orreplace
Plug.
Smokes
excessivelY lncorrect carburetor mixture
adjustment
setting Have
carburetor
adiusted
bY
Authorized
Service
Center. an
lncorrect
fuel
mixture Use
properly
mixed
fuel
(40:1
mixture)
.
FOR
WARRANWOR
SERVICE
CONTACT
THE
NEAREST
MCCULLOCH
AUTHORIZED
SERVICE
CENTER
LISTED
UNDER
''SAWS'
IN
YOUR
TELEPHONE
DIRECTORY
YELLOW
PAGES.
IF
FURTHER
ASSISTANCE
IS
REQUIRED
CALL
THIS
TOLL-FREE
HOT
LINE'
PLEASE
REFERENCE
YOUR
MODEL
AND
SERIAL
NUMBER'
1€00423-6302
lnArizona:
1-800-221-6s07
M-F
6:00
AM
-
4:45
PM
(MST)