Craftsman 316.77237 User Manual

Page 11

NOTE: If the unit is operated without the air filter, you will VOID the

warranty.

Reinstall the air filter cover. Position the tabs on the sides of the
air filter cover onto the slots at the top of the back plate (Fig. 25).

Push the cover in until the tab on the air filter backplate snaps
into place in the slot on the air filter cover (Fig. 25).

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. 29).
NOTE: Careless adjustments can

seriously damage your
unit. Aside from the idle speed, only a Sears or other
qualified service dealer should make carburetor adjustments.

1. 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.
2. 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

Fig. 25

Air Filter

Screen

Air Filter Cover

Air Filter Housing

Tab

Hooks

Air Filter

Slot

Fig. 26

Fig. 27

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

3. 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.

Move the throttle control
lever to the Slow position (

) and let the engine idle. If the

engine stops, insert a small phillips in between the Air Filter
Cover and the Engine Cover (Fig. 29).

NOTE: Do not engage the Blade Clutch Lever while adjusting the

idle speed screw to ensure that the blade will not rotate.

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
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 every 25
hours of operation.

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

clearance.

• This task should be performed inside, in a clean, dust free area.
1.

Remove the six (6) screws on the back of the engine cover with a
Flat-head or T-25 Torx screwdriver (Fig. 30).

Disconnect the spark
plug wire.

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

Remove the engine
cover (Fig. 30).

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. 31).
Remove the rocker
arm cover and gasket.

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.

Look in the spark plug hole to view
the piston (Fig. 32)

• 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

Fig. 28

Fig. 29

Idle

Adjustment

Screw

Fig. 30

Remove

Screws

Remove

Screws

Fig. 31

Rocker Arm

Cover

Spark

Plug
Hole

WARNING:

prevent serious
personal injury, make
sure the blade has
stopped rotating
before you turn it off.

MAINTENANCE AND REPAIR INSTRUCTIONS