Murray 425007x92C - Manual (Page 21)

MAINTENANCE
21 F–030723L
INSPECT BLADE
WARNING: Before you inspect or remove the blade,
disconnect the wire to the spark plug. If the blade hits
an object, stop the engine. Check the unit for dam-
age. The blade has sharp edges. When you hold the
blade, use gloves or cloth material to protect your
hands.
If you keep the blade sharp and inspect the blade for damage, the
blade will cut better and be more safe to operate. Frequently check
the blade for excessive wear, cracks, or other damage. Frequently
check the nut that holds the blade. Keep the nut tight. If the blade
hits an object, stop the engine. Disconnect the wire to the spark plug.
See if the blade is bent or damaged. Check the blade adapter for
damage. Before you operate the unit, replace damaged parts with
original equipment parts. See the authorized service center in your
area. Every three years, have an authorized service person inspect
the blade or replace the old blade with an original equipment part.
HOW TO REMOVE AND INSTALL THE BLADE
1. Remove the mower housing. See the instructions on “How To
Remove The Mower Housing”.
2. Use a piece of wood to keep the blade from rotating.
3. Remove the nut that holds the blade (Figure 10).
Hi–Lift
Edge Up
Mandrel
Blade Adapter
Blade
Belleville Washer
Washer
Nut
Figure 10
4. Check the blade and the blade adapter according to the in-
structions for “Inspect Blade”. Replace a badly worn or dam-
aged blade with an original equipment blade. See an
authorized service center in your area.
5. Clean the top and bottom of the mower housing. Remove all the
grass and debris.
6. Mount the blade and blade adapter on the mandrel
(Figure 10).
7. Mount the blade so that the hi–lift edges are up. If the blade
is upside down, the blade will not cut correctly and can cause
an accident.
8. Fasten the blade with the original washers and nut. Make sure
the outside rim of the Belleville washer is against the blade
(Figure 11).
WARNING: Always keep the nut tight that holds the
blade. A loose nut or blade can cause an accident.
9. Tighten the nut that holds the blade to a torque of 35 foot
pounds (47,5 N–m).
10. Install the mower housing. See “How To Install The Mower
Housing”.
Blade Adapter
Blade
Belleville Washer
(Outside rim must be
against the blade.)
Washer
Nut
Figure 11
HOW TO SHARPEN THE BLADE
WARNING: Vibration can be caused if the blade is
not correctly balanced or if the blade is damaged. A
blade that is damaged with cracks can break and
cause an accident.
Keep a sharp edge on the blade. A blade that is not sharp will cause
the tips of the grass to become brown.
1. Sharpen the blade two times a year or every 25 hours.
2. Remove the blade according to the instructions in “How To Re-
move And Install The Blade”.
3. Clean the blade with a brush, soap and water. Check the
blade. Look for cracks, nicks, or other damage. Replace a
badly worn or damaged blade with an original equipment blade.
See an authorized service center in your area.
4. Sharpen the blade with a file (Figure 12). Make sure you keep
the original bevel angle.
5. Make sure the blade is balanced. Use a screwdriver and hold
the blade parallel to the ground (Figure 12). A blade that is
balanced will stay parallel to the ground. If the blade is not bal-
anced, 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 three
years, have an authorized service person inspect the blade or
replace the old blade with an original equipment blade.
7. Assemble the blade according to the instructions “How To Re-
move And Install The Blade”.
Ground
Blade is balanced
when parallel to the ground.
Screwdriver
Blade
File
Figure 12