Craftsman 316.79479 manual Carburetoradjustment

CARBURETORADJUSTMENT

The idle speed of the engine is adjustable. An idle adjustment screw is between the air filter cover and the engine starter housing (Fig. 24).

Idle Adjustment

Screw

Remove	Remove
Screws
	Screws

Fig. 25

Fig. 24

4.Replace cracked, fouled or dirty spark plug. Set the air gap at 0.025 in. (0.635 mm.) using a feeler gauge (Fig. 26).

5.Install a correctly-gapped spark plug in the cylinder head. Turn the 5/8 in. socket clockwise

until snug.

0.025 in.

(0.635,_mm.) _ ,

NOTE: Careless adjustments can seriously damage your unit. An authorized service dealer should make carburetor adjustments.

Check Fuel

Old and!or improperly mixed fuel is usually the reason for improper unit performance. Drain and refill the tank with fresh, properly-mixed 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.

2.Release the trigger lock and let the engine idle. If the engine stops, insert a small phillips in between the Air Filter Cover and the Engine Cover (Fig. 24). 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 mixture, 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.

REPLACING THE SPARK PLUG

Use a Champion #RDZ4H or a replacement part #753-05784 spark plug. The correct air gap is 0.025 in. (0.635 mm.). Remove the plug after every 25 hours of operation and check its condition.

1.Stop the engine and allow it to cool. Remove the four (4) screws on the back of the engine cover with a Flat-head or T- 25 Torx screwdriver (Fig. 25).

2.Grasp the plug wire firmly and pull the cap from the spark plug.

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

WARNING: Do not sand blast, scrape or clean electrodes. Grit in the engine could damage the cylinder.

If using a torque wrench torque to: 110-120 in.•lb. (12.3-13.5 N•m)

Do not over tighten.	Fig. 26
SPARK ARRESTOR MAINTENANCE

Inspect the spark arrestor after every 50 hours of operation.

1.Remove the rear engine cover (Fig. 25).

2.With a flat blade screwdriver or Torx T-25 bit, remove the 2 screws attaching the muffler to the engine (Fig. 27).

3"-25 Screws

Muffler

Fig. 27

3.With a flat blade screwdriver or Torx T-20 bit, remove the screw attaching the spark arrestor cover to the muffler (Fig. 28).

3"-20 Screw

Spark

Arrestor

Spark Arrestor Cover

Fig. 28

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