MTD 769-01445 Lawn Mower User Manual


 
13
Figure 13
Installing the Blade
WARNING: The blade hardware is not only
used to attach the blade assembly, but is
also an insulated safety device and should
never be altered in any way. If replacement
is necessary, use original equipment parts
as shown in the parts list on page 17.
Place the cutting blade, locking plate, and blade
bolt against the blade hub assembly and thread the
blade bolt on finger tight. Refer to Figure 13.
NOTE: Make certain to replace the parts in the exact
order in which they were removed. When installing the
cutting blade, make sure it is installed with the curved
ends pointing towards the mower deck and not towards
the ground.
Torque the blade bolt down using a torque wrench
to assure the bolt is tightened properly. The
recommended torque for the blade bolt is 450-600
in. lbs. To insure safe operation of your unit, all nuts
and bolts must be checked periodically for correct
tightness.
Sharpening the Blade
To sharpen the blade, first remove the blade as outlined
in the previous section. DO NOT attempt to sharpen the
blade while it is attached to the mower. The blade can
be sharpened with a file or on a grinding wheel.
When sharpening the blade, follow the original
angle of grind as a guide. It is extremely important
that each cutting edge receives an equal amount of
grinding to prevent an unbalanced blade.
Test the blade by balancing it on a round shaft
screwdriver or a blade balancer. See Figure 14.
If the blade is not balanced, remove metal from the
heavy side until it balances evenly.
WARNING: An unbalanced blade will cause
excessive vibration when rotating at high
speeds. It may also cause damage to the
mower and could break, causing personal
injury.
Reinstall the blade as described earlier in this
section making certain to torque the cutting blade to
specifications.
Figure 14
Mower Deck
WARNING: To reduce the risk of electric
shock, do not expose the mower to water.
The underside of mower deck should be cleaned after
each use as grass clippings, leaves, dirt and other
debris will accumulate. This accumulation of grass
clippings, etc., is undesirable as it will promote rust and
corrosion.
Remove any buildup of grass and leaves on or
around the motor cover (do not use water). Wipe
the mower clean with a dry cloth occasionally.
If debris is allowed to build up on the underside of
the unit, stop the motor and disconnect the power
supply to the mower, tilt the mower forward or on its
side and scrape it clean with a suitable tool.
Lubrication
At the beginning and end of each mowing season:
Lubricate the springs on the rear discharge door
with a light oil.
Lubricate the height adjustment levers and related
hardware with light oil.
Remove the wheels and lubricate the surface of the
axle bolt and the inner surface of the wheel with
light oil.
Remove the blade and blade hub assembly and
lubricate the motor shaft with light oil or engine oil.
Refer to Figure 13.
Cutting Blade
Locking Plate
Blade Bolt
Motor Shaft
1. Insert screwdriver through hole
2. Balanced blade will be parallel to ground
Screwdriver
Ground
Blade