CARBURETOR ADJUSTMENT

The idle speed of the engine is adjustable through the air filter/muffler cover, Figure 26.

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

Check Fuel Mixture

Old and/or improperly mixed fuel is usually the reason for the unit not running properly. Drain and refill the tank with fresh, properly mixed fuel prior to making any adjustments. Refer to Oil and Petrol Information.

Idle Speed Screw

FIGURE 26

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 and change the air/fuel mixture. 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.

Adjusting the Idle Speed

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

If after checking the fuel mixture and cleaning the

air filter the engine still will not idle, adjust the idle speed as follows.

1.Start the engine and let it run at a high idle for a minute to warm up. See Starting/Stopping Instructions.

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, Figure 26. Turn the idle speed screw in, clockwise, 1/8 of a turn at a time (as needed) until the engine idles smoothly.

3.If the engine appears to be idling too fast, turn the idle speed screw out, counterclockwise, 1/8 of a turn at a time (as needed) to reduce idle speed.

NOTE: If a tachometer is available, set idle speed to RPM specifications in Specifications section.

Checking the fuel mixture, cleaning the air filter, and adjusting the idle speed should solve most engine problems.

If not and:

•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.

WARNING: When the unit is turned off make sure the cutting head has stopped before the unit is set down to prevent serious personal injury.

REPLACING THE SPARK PLUG

Use a Champion RDJ7Y spark plug (or equivalent). The correct air gap is 0.5 mm (0.020 in.). Remove the plug after every 25 hours of operation and check its condition.

1.Stop the engine and allow it to cool. Grasp the plug wire firmly and pull the cap from the spark plug.

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

NOTE: Replace cracked, fouled or dirty spark plug.

3.Set the air gap at 0.5 mm (0.020 in.) using a feeler gauge, Figure 27.

0.5 mm

(0.020 in.)

FIGURE 27

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

4.Install a correctly gapped spark plug in the cylinder head. Tighten by turning the 5/8 in. socket clockwise until snug.

If using a torque wrench torque to:

12.3-13.5 N•m (110-120 in.•lb.)

Do not over tighten.

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