Yard Machines 769-00872A - Manual (Page 13)

13
MAINTENANCE AND REPAIR INSTRUCTIONS
REPLACING THE SPARK PLUG
Use a Champion RDJ7Y spark plug (or equivalent). The
correct air gap is 0.020 in. (0.5 mm). Remove the plug
after every 25 hours of operation to 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 a cracked, fouled or dirty spark plug.
3. Set the air gap at 0.020 in. (0.5 mm) using a feeler
gauge (Fig. 19).
Adjust Idle Speed Adjuster
If after checking the fuel mixture 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 for about 2-3 minutes
at a high speed (full throttle) to warm up. Refer to the
Starting/Stopping Instructions.
NOTE: Ensure the tines are not in contact with the
ground when adjusting the idle.
2. Release the throttle control and let the engine idle. If
the engine stops, insert a small phillips or flat blade
screwdriver into the hole in the muffler cover (Fig. 18).
Turn the idle speed screw clockwise 1/8 of a turn at
a time (as needed) until the engine idles smoothly.
NOTE: The tines should not rotate during engine idle.
3. If the tines rotate when the engine idles, turn the idle
speed screw 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 screw should solve most engine
problems. If not and all 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 Adjuster
Muffler - Front Side Muffler - Back Side
Bolts
Exhaust
Gasket
Spark
Arrestor
Muffler - Back Side
Spark Arrestor
Flatblade
Screwdriver
Spark
Arrestor
CARBURETOR ADJUSTMENTS
The engine’s idle speed adjuster is adjustable through
the air filter/muffler cover (Fig 18).
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 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 adjuster. Refer to
Air Filter Maintenance.
8. Place the muffler (with the exhaust gasket in place and
bolts inserted), against the engine, aligning the bolt
holes. Tighten the bolts to secure the muffler to the
engine. If using a torque wrench, torque to:
80-90 in.•lb. (9-10.2 N•m)
9. Reinstall the air filter/muffler cover.
Fig. 18
Fig. 17
Fig. 16
If the muffler is not
tightened securely, it
could fall off causing damage to the unit and
possible serious personal injury.
WARNING:
Do not sand blast,
scrape or clean
electrodes. Grit in the engine could damage
the cylinder.
CAUTION:
The unit will still run
during idle speed
adjustments. Wear protective clothing and
observe all safety instructions to prevent
serious personal injury.
WARNING: