Fig. 31
Idle
Adjustment
Screw

MAINTENANCE AND REPAIR INSTRUCTIONS

NOTE: It may be necessary to remove the fuel cap to reinstall the air filter cover.

8.Swing the cover to the right until the tab on the air filter cover snaps into place in the slot on the back plate (Fig. 30).

9.Replace the fuel cap if it was removed.

CARBURETOR

ADJUSTMENT

Fig. 29

Air Filter Cover

Air Filter

Tab

Fig. 30

•This task should be performed inside, in a clean, dust free area.

1.

Remove the muffler

 

cover by pressing

 

down on it,

 

separating it from the

 

engine cover. Using

 

a flat blade

 

screwdriver,

 

disengage the

 

middle and front

 

tabs and slots first.

 

The cover will hinge

 

off from the rear tab

 

(Fig. 32).

2.

Remove the two (2)

Engine Cover

 

Rear

Middle Tab

Front Tab

 

Slot &

 

 

Tab

 

 

Middle Slot

Front Slot

 

Fig. 32

 

 

Top View Of The Engine

Engine Cover

Remove Screws

Muffler

WARNING: The cutting attachment may spin during idle speed adjustments. Wear protective clothing and observe all safety instructions to prevent serious personal injury.

The idle speed of the engine is adjustable. An idle adjustment screw is reached though a hole

in the top of the engine cover (Fig. 31).

screws on top of the

engine cover with a

Flat-head or T-25

Torx screwdriver

(Fig. 33).

3. Remove the screw

behind the engine

cover (Fig. 34).

Fig. 33

Screw

NOTE: Careless adjustments can seriously damage your

unit. An authorized

service dealer should make carburetor adjustments.

Check Fuel

Old fuel is usually the reason for improper unit performance. Drain and refill the tank with fresh fuel prior to making any adjustments. Refer to Oil and Fuel Information.

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 carburetor. Check the condition of the air filter before adjusting the idle speed screw. Refer to Air Filter Maintenance.

Adjust Idle Speed Screw

If, after checking the fuel and cleaning the air filter, the engine still will not idle, adjust the idle speed screw as follows:

1. Start the engine and let it run at a high idle for a minute to warm

up. Refer to Starting/Stopping Instructions.

4.Disconnect the spark plug wire.

5.Clean dirt from around the spark plug. Remove the spark plug from the cylinder head by turning a 5/8 in. socket counterclockwise.

6.Remove the engine cover (Fig. 33).

7.Clean dirt from around the rocker arm cover. Remove the screw holding the rocker arm cover with a large flat blade screwdriver or Torx T-25 bit (Fig. 35). Remove the rocker arm cover and gasket.

Fig. 34

Rocker Arm Cover

Spark

Plug

Hole

Fig. 35

 

Rocker Arms Intake

Adjustment

 

Nuts

 

Exhaust

Feeler Gauge

 

Fig. 36

 

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. 31). Turn the idle speed

screw in, clockwise, 1/8 of a turn at a time (as needed) until

the engine idles smoothly.

Checking the fuel, cleaning the air filter, and adjusting the idle speed should solve most engine problems. If not and all of the following are true:

•the engine will not idle

•the engine hesitates or stalls on acceleration

•there is a loss of engine power

Have the carburetor adjusted by an authorized service dealer.

ROCKER ARM CLEARANCE

WARNING: To prevent serious personal injury, make sure the cutting attachment has stopped rotating before you turn it off and set it down.

This requires disassembly of the engine. If you feel unsure or unqualified to perform this, take the unit to an authorized service center.

NOTE: Inspect the valve to rocker arm clearance with a feeler gauge after the first 10 hours of operation and then every 25 hours of operation thereafter.

•The engine must be cold when checking or adjusting the valve clearance.

8.Pull the starter rope slowly to bring the piston to the top of its travel, (known as top dead center). Check that:

•The piston is at the top of its travel while looking in the spark

plug hole (Fig. 36)

Exhaust

 

• Both rocker arms

Adjustment Nut

Feeler Gauge

move freely, and

Exhaust

 

both valves are

Clearance:

 

closed

.003-.006 in.

 

If these statements

(.076-0.152 mm)

Exhaust

are not true, repeat

Intake Clearance:

Valve Stem

this step.

.003–.006 in.

 

9. Slide the feeler (.076–0.152 mm) Intake Valve Stem

gauge between the

 

Fig. 37

 

rocker arm and the

 

 

 

 

 

valve return spring. Measure the clearance between the valve stem and rocker arm (Fig. 36). Measure both the intake and exhaust valves.

The recommended clearance for the intake and exhaust is .003 –

.006 in. (.076 – 0.152 mm). Use a standard automotive feeler gauge at .005 in. (0.127mm). The feeler gauge should slide between the rocker arm and valve stem with a slight amount of resistance, without binding. Figure 37 shows how to measure the clearance.

10. If the clearance is not within specification:

a. Turn the adjusting nut using a 5/16 inch (8 mm) wrench or nut driver (Fig. 36).

8