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. 27). NOTE: Careless adjustments can seriously damage your unit. A Sears
or other qualified 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
WARNING: This unit will need to be running during idle speed adjustment. Wear protective clothing and observe all safety instructions to prevent serious personal injury.
Muffler
Cover
\
Starter
Housing
Screws (2)
Starter
Housing
(4)
Muffler Cover
Screws (2)
Fig. 28
Also, DO NOT set unit on any surface except a clean, hard area while starting or performing any adjustments. Debris, such as gravel, sand, dust, grass, etc., could be thrown by the blower tube and damage property or cause serious injury to bystanders or operator.
If, after checking the fuel and cleaning the air filter, the engine still will not
• The piston is at the top of its travel |
|
by looking in the spark plug hole |
|
(Fig. 30) |
|
• Both rocker arms move freely, and | Spark |
both valves are closed. | |
If these statements are not true, repeat | Plug Hole |
| |
this step. |
|
Arm
Cover
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.
2.Release the trigger and let the engine idle. If the engine stops, insert a small phillips screwdriver in between the Air Filter Cover and the Engine Cover (Fig. 27). 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:
Idle Speed Few
7.Slide the feeler gauge between the rocker arm and the valve
return spring. Measure the clearance between the valve stem
and rocker arm (Fig. 30 & 31). Measure both the intake and exhaust valves.
INTAKE
Rocker Arms
Fig. 29
Adjusting Nuts
O-Ring
• the engine will not idle | Fig. 27 | |
|
|
•the engine hesitates or stalls on acceleration
•there is a loss of engine power
take the unit to a Sears or other qualified service dealer.
ROCKER ARM CLEARANCE
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 dealer.
NOTE: Inspect the valve to rocker arm clearance with a feeler gauge after the first 10 hours of operation and every 40
hours of operation.
•The engine must be cold when checking or adjusting the rocker arm clearance.
•This task should be performed inside, in a clean, dust free area.
1.Remove the 2 muffler cover screws with a flat blade or
2.Remove the 6 starter housing screws with flat blade or
NOTE: Make sure to store the screws so that they can be reinstalled into their original holes.
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. socket counterclockwise.
5.Clean dirt from around the rocker arm cover. Remove the screw holding the rocker arm cover with a large flat blade screwdriver or Torx
6.Turn the flywheel slowly to bring the piston to the top of its travel (known as top dead center). Check that:
Feeler Gauge
Fig. 30
Adjusting Nut
Rocker Arm
Feeler Gauge
Valve Stem
Fig. 31
12
