21
6
Maintaining
Your Lawn
Tractor
WARNING
Periodically inspect
the blade spindles for
cracks or damage,
especially if you strike
a foreign object.
Replace immediately if
damaged.
Be sure to shut the
engine off, remove
ignition key, discon-
nect the spark plug
wire(s) and ground
against the engine to
prevent unintended
starting before remov-
ing the cutting blade(s)
for sharpening or
replacement. Protect
your hands by using
heavy gloves or a rag
to grasp the cutting
blade.
Cutting Blades
WARNING: Be sure to shut
the engine off, remove ignition
key, disconnect the spark plug
wire(s) and ground against the
engine to prevent unintended
starting before removing the cut-
ting blade(s) for sharpening or
replacement. Protect your hands
by using heavy gloves or a rag to
grasp the cutting blade.
WARNING: Periodically inspect
the blade spindles for cracks or
damage, especially if you strike a
foreign object. Replace immedi-
ately if damaged.
The blades may be removed as follows.
1. Remove the deck from beneath the tractor, (refer to
Cutting Deck Removal on page 19) then gently flip
the deck over to expose its underside.
2. Place a block of wood between the center deck hous-
ing baffle and the cutting blade to act as a stabilizer.
See Figure 18.
3. Use a 15/16” wrench to remove the hex flange nut
that secures the blade to the spindle assembly. See
Figure 18.
4. To properly sharpen the cutting blades, remove equal
amounts of metal from both ends of the blades along
the cutting edges, parallel to the trailing edge, at a
25° to 30° angle.
IMPORTANT
: If the cutting edge of the blade has already
been sharpened to within 1 5/8” from the edge, or if any
metal separation is present, replace the blades with new
ones. See Figure 19.
• It is important that each cutting blade edge be ground
equally to maintain proper blade balance.
• A poorly balanced blade will cause excessive
vibration and may cause damage to the tractor and
result in personal injury. The blade can be tested by
balancing it on a round shaft screwdriver. Grind metal
from the heavy side until it balances evenly.
• When replacing the blade, be sure to install the blade
with the side of the blade marked ‘‘Bottom’’ (or with
a part number stamped in it) facing the ground when
the mower is in the operating position.
IMPORTANT
: Use a torque wrench to tighten the blade
spindle hex flange nut to between 70 foot-pounds and 90
foot-pounds.
Figure 18
����������
Figure 19
Hex Nut
Summary of Contents for 77T Series
Page 23: ...23 6 Maintaining Your Lawn Tractor Figure 21...
Page 30: ...30 Models 77T...
Page 36: ...36 Models 760 779...
Page 38: ...38 Models 760 779...
Page 42: ...42 Models 77T 20 13 21 14 10 18 12 11 22 19 23 3 9 4 17 15 8 6 7 16 2 5 1...
