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NOTE: I ftheunit i soperated
without theairfilter,
youwill V OID the
warranty.
7. Reinstall theairfilter
cover. Position thetwo
small tabsontheairfilter
cover i ntothetwoslots in
thebackplate andpress
theairfilter cover d own,
making s ure toalign the
locktabwiththelocktab
slot,until i tsnaps i nto
place (Fig. 3 4&33).
IDLE SPEED ADJUSTMENT
The idle speed of the engine is
adjustable. An idle adjustment
screw is between the air filter
cover and the engine starter
housing (Fig. 39).
NOTE:
Careless adjustments
can seriously damage
the unit. Aside from
idle speed, only a
Sears or other
authorized service
dealer should make
carburetor
adjustments.
First, Check Fuel
Fig. 36
Fig. 37
Black
Fig. 38
Air
Filter
Old fuel is usually the reason for idle speed problems. Drain and
refill the tank with fresh fuel prior to making any adjustments.
Refer
to Oil and Fuel Information.
Second, Clean Air Filter
The condition of the air filter is important to the operation of the unit.
A dirty air filter will restrict air flow. This is often mistaken for an out
of adjustment
idle. Check the condition of the air filter before
adjusting the idle speed screw. Refer to Air Filter Maintenance.
Third, Adjust Idle Speed Screw
_
ARNING:
The cutting attachment
may spin during idle
speed adjustments.
Wear protective clothing and observe
a safety nstruct ons to prevent serous persona
njury,
j
If, after checking the fuel and cleaning the air filter, the engine still
will not idle, adjust the idle speed screw as follows:
Start the engine and let it
run at a high idle for a
minute to warm up. Refer
to Starting/Stopping
instructions.
Idle Adjustment
( _1
Screw
Fig. 39
1.
2.
Release the throttle
trigger and let the engine
idle. If the engine stops,
insert a small phillips or
flat blade screwdriver
into
the hole in the air filter/muffler
cover (Fig. 39). Turn the idle
speed screw in, clockwise,
1/8 of a turn at a time (as needed)
until the engine idles smoothly.
NOTE:
The cutting attachment
should not rotate when the engine
idles.
3.
If the cutting attachment
rotates when the engine idles, turn the
idle speed screw counterclockwise
1/8 of a turn at a time (as
needed), to reduce idle speed.
Checking the fuel, cleaning the air filter, and adjusting the idle speed
should solve most engine problems. If not and any of the following are
true have the unit serviced by a Sears or other qualified service dealer:
• the engine will not idle
• the engine hesitates or stalls on acceleration
• there is a loss of engine power
10
ROCKER ARM CLEARANCE
--
m
I ,_
I WARNING:
To avoid serious personal injury,always turn your I
I _lb
I trimmer off and allow it to cool before you clean or maintain it.
This requires disassembly
of the engine. If you feel unsure or
unqualified to perform this, take the unit to a Sears or other qualified
service center.
Remove Screws
NOTE:
inspect the valve to
rocker arm clearance
with a feeler gauge
after the first 25 hours
of operation and then
every 25 hours of
operation thereafter.
The engine must be cold
when checking or adjusting
Fig. 40
the valve clearance.
Engine
This task should be
Cover
performed inside in a clean,
dust free area.
1.
Remove the two (2) screws
on back of the engine
cover and the one on the
front of the engine cover
with a Flat-head or T-25
Torx screwdriver (Fig. 40).
2.
Remove the engine cover
(Fig. 41).
3.
Disconnect
the spark plug
wire.
4.
Clean dirt from around the
spark plug. Remove the
spark plug from the
cylinder head by turning a
5/8 in. (16 mm) socket
counterclockwise.
Fig. 41
Screw _
Rocker
Arm
Cover
Spark
Plug Hole
Fig. 42
Adjusting Nuts
5.
Clean dirt from around the
INTAKE
rocker arm cover. Remove
the screw holding the
EXHAUST
rocker arm cover with a
Rocker
large flat blade
Arms
screwdriver or Torx T-25
bit (Fig. 42). Remove the
rocker arm cover and
gasket.
Fig. 43
Exhaust
Rocker Arm
6.
Pull the starter rope
Adjusting--_-_
/
slowly to bring the piston
Nut
__
"/
GaugeFeeler
to the top of its travel,
(known as top dead
I
t___"_
./
center). Check that:
0.003--0.006 in
The piston is at the top of its (0.076-0.152 ram)
travel. This should be done
by looking intothe spark
_Valve
Stem
plug hole. (Fig. 42)
Fig. 44
Both rocker arms move freely, and both valves are closed
If these statements are not true, repeat step 6.
7.
Slide the feeler gauge between the rocker arm and the top of
each valve stem. Measure the clearance between the valve
stem and rocker arm (Fig. 43). Measure both the intake and
exhaust valves.
The recommended clearance for both intakeand exhaust is .003 - .006 in.
(.076 - 0.152 mm). Use a standard automotive .005 in. (0.127 ram) feeler
gauge. The feeler gauge should slide between the rocker arm and valve
stem with a slight amount of resistance, without binding. Figure 43 and 44
show how to measure the clearance.
8.
a.
If the clearance is not within specification:
Turn the adjusting nut using a 5/16 inch (8 ram) wrench or nut driver
(Fig. 43).
To increase clearance, turn the adjusting nut counterclockwise.
To decrease clearance, turn the adjusting nut clockwise.
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