Murray 22" Self-Propelled - Manual (Page 23)

MAINTENANCE
23 F-050408L
BLADE SERVICE
WARNING: Before you inspect
the blade or the blade adapter,
disconnect the wire to the spark
plug. If the blade hits an object, stop the
engine. Disconnect the wire to the spark
plug. Check the unit for damage.
Frequently check the blade for wear or dam-
age such as cracks. Frequently check the bolt
that holds the blade. Keep the bolt tight. If the
blade hits an object, stop the engine. Discon-
nect the wire to the spark plug. Check the
blade adapter for damage. Check for a bent or
damaged blade, a badly worn blade, or other
damage. Before you operate the unit, dam-
aged parts must be replaced with factory re-
placement parts. For safety, replace the blade
every two years. Keep a sharp edge on the
blade. A blade that is not sharp will cause the
ends of the grass to become brown. Remove
the blade as follows.
HOW TO REMOVE THE BLADE
WARNING: Before you remove
the blade, disconnect the wire
to the spark plug. The blade has
sharp edges. When you hold the blade,
use gloves or cloth material to protect
your hands.
1. Drain the fuel tank.
2. Lift the side of the mower that has the
muffler or spark plug.
3. Use a piece of wood to keep the blade
from rotating.
4. Remove the bolt that holds the blade with
a 9/16” (14mm) wrench.
5. Check the blade according to the “Blade
Service” instructions. Replace a badly
worn or damaged blade with a factory re-
placement blade.
6. Mount the blade with the curved edges to-
ward the housing. If the blade is upside
down, the blade will not cut correctly and
can cause an accident.
7. Fasten the blade with the original washer
and bolt. Make sure the outside rim of the
Belleville washer is toward the blade
(Figure 29).
8. Tighten the bolt that holds the blade to a
torque of 30 foot pounds.
WARNING: Always keep the bolt
that holds the blade tight. A loose
bolt or blade can cause an acci-
dent.
Blade
Adapter
Blade
Belleville
Washer
Bolt
ППППП
ММММ
ММММ
ММММ
ПП
ПП
ММ ММ
С
С
Belleville Washer
Bolt
Blade Adapter
Blade
Figure 29
HOW TO SHARPEN THE BLADE
WARNING: Vibration is the re-
sult if the blade is not correctly
balanced. A blade that is dam-
aged with cracks can break and cause an
accident.
1. Sharpen the blade two times a year or ev-
ery 25 hours.
2. If the blade is on the unit, do not sharpen.
Remove the blade according to the in-
structions in “How To Remove The Blade”.
3. Clean the blade with a brush, soap, and
water. Check the blade. Look for cracks,
nicks, or other damage. Replace a blade
that is badly worn, bent, or damaged with
a factory replacement blade.
4. Sharpen the blade with a file. Make sure
you keep the original beveled cutting edge
(Figure 30).
5. Make sure the blade is balanced. Use a
screwdriver and hold the blade parallel to
the ground as shown. A blade that is bal-
anced will stay parallel to the ground. If the
blade is not balanced, the heavy end will
rotate toward the ground. Sharpen the
heavy end until the blade is balanced.
6. A new blade will cut better than a badly
worn blade. Every two years replace the
old blade with a factory replacement
blade.
CHECK THE LEVEL OF CUT
Test the unit in a small area. If the height of cut
is not level or if the cut grass is not discharged,
the cause can be: (1) the blade is bent or dam-
aged, (2) the blade is not sharp, (3) a worn
blade, (4) or a broken blade adapter. Before
you use the unit, correct the problem.