Troy-Bilt TB425 XP Manual Del Operador página 20

ADJUSTING THE IDLE SPEED
WARNING:
The cutting head / blade may spin during idle
speed adjustments. Wear protective clothing and observe all
safety instructions to prevent serious personal injury.
If the engine will not idle properly:
1. Start the engine. Refer to Starting and Stopping.
2. Release the throttle control and let the engine idle.
• If the engine stops, increase the idle speed. Use a small
Phillips screwdriver to turn the idle speed screw clockwise,
1/8 of a turn at a time, until the engine idles smoothly (Fig. 38).
• If the cutting head / blade spins when the engine idles, reduce
the idle speed. Turn the idle speed screw counterclockwise,
1/8 of a turn at a time, until the cutting head / blade stops
moving (Fig. 38).
MAINTAINING THE SPARK PLUG
WARNING:
Do not sand blast, scrape or clean spark plug
electrodes. Grit in the engine could damage the cylinder.
1. Stop the engine and allow it to cool.
2. Remove the three (3) screws from the engine cover with a flat-
head screwdriver or T-25 Torx screwdriver (Fig. 39). Remove the
engine cover.
3. Grasp the spark plug boot firmly and pull it from the spark plug.
4. Clean around the spark plug. Remove the spark plug from the
cylinder head with a 5/8-inch socket, turning counterclockwise.
5. Inspect the spark plug. If the spark plug is cracked, fouled or
dirty, replace it with replacement part #794-00082, a Champion
RDZ4H or an equivalent spark plug.
6. Use a feeler gauge to set the air gap at 0.025 in. (0.635 mm)
(Fig. 40).
7. Install the spark plug in the cylinder head. Tighten the spark plug
with a 5/8-inch socket, turning it clockwise until snug.
NOTE: If using a torque wrench, torque to:
110-120 in.•lb. (12.3-13.5 N•m). Do not over tighten.
8. Reattach the spark plug boot.
9. Reinstall the engine cover. Check the alignment of the engine
cover before tightening the screws. Tighten the screws.
Engine Cover
Front
0.025 in.
(0.635 mm)
20
Idle Speed Screw
Fig. 38
Engine Cover
Screws
Back
Fig. 39
Fig. 40