MAINTENANCE AND REPAIR INSTRUCTIONS

CARBURETOR ADJUSTMENT

The idle speed of the engine is adjustable through the air filter/muffler cover (Fig. 29).

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 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 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.

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.

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 picked up by the air intake and thrown out by the discharge opening, damaging unit, property, or causing serious injury to bystanders or operator.

If after checking the fuel mixture and cleaning the air filter the engine still will not idle, adjust the idle speed adjuster as follows.

1.Start the engine and let it run at the fast position for a minute to warm up.

2.Set the blower/vacuum mode change-over lever to the up position (Blower Mode). Refer to Operating as a Blower.

NOTE: Setting the lever to the blower mode prevents the vacuum bag from filling up while starting or running the unit.

3.Move the throttle control and let the engine idle. If the engine stops, insert a small phillips screwdriver into the hole in the air filter/muffler cover (Fig. 29). Turn the idle speed adjuster in, clockwise, 1/8 of a turn at a time (as needed) until the engine idles smoothly.

4.If the unit appears to be idling too fast, turn the idle speed adjuster counterclockwise 1/8 of a turn at a time (as needed), to reduce idle speed.

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.

Idle Speed Screw

Fig. 29

REPLACING THE SPARK PLUG

Use a Champion RDJ7Y spark plug, or equivalent. The correct air gap is 0.020 inch (0.5 mm). 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 it from the spark plug.

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

3.Replace a cracked, fouled or dirty spark plug. Set the air gap at 0.020 in. (0.5 mm) using a feeler gauge (Fig. 30).

WARNING: 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-inch socket clockwise until snug.

If using a torque wrench torque to:

110-120 in.•lb. (12.3-13.5 N•m) Do not over tighten.

0.020 in.

(0.5 mm)

Fig. 30

18