Cutting Blades; Changingthe Deckbelt - MTD Series 770 Operator's Manual

Cutting Blades
WARNING! Shut the engine off and remove
ignition key before removing the cutting blade(s) for
sharpening or replacement. Protect your hands by
using heavy gloves when grasping the blade.
WARNING! Periodically inspect the blade and/or
spindle for cracks or damage, especially after you've
struck a foreign object. Do not operate the machine
until damaged components are replaced.
To remove the blades, proceed as follows.
1. Remove the deck from beneath the tractor, (refer to
Cutting Deck Removal earlier in this section) then gently
flip the deck over to expose its underside.
2. Place a block of wood between the center deck housing
baffle and the cutting blade to act as a stabilizer.
See Fig. 7-4.
3. Remove the hex flange nut that secures the blade to the
spindle assembly. See Fig. 7-4.
Figure 7-4
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. Always grind each cutting blade edge equally to
maintain proper blade balance. See Fig. 7-5.
CAUTION: If the cutting edge of the blade has
previously been sharpened, or if any metal
separation is present, replace the blades with new
ones.
_ WARNING! A poorly balanced blade will cause
excessive vibration, may damage to the tractor and/
or result in personal injury.
5. Test the blade's balance using a blade balancer. Grind
metal from the heavy side until it balances evenly.
Figure 7-5
NOTE: 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.
CAUTION:
Use a torque wrench to tighten the
blade spindle hex flange nut to between 70 Ibs-ft
and g0 Ibs-ft.
Changingthe DeckBelt
i_ WARNING! Be sure to shut tile engine off, remove
ignition key, disconnect the spark plug wire(s) and
ground against the engine to prevent unintended
starting before removing the belt.
WARNING! All belts on your tractor are subject to
wear and should be replaced if any signs of wear are
present.
IMPORTANT: The V-belt found on your tractor is specially
designed to engage and disengage safely. A substitute (non-
OEM) V-beh can be dangerous by not disengaging completely.
For a proper working machine, use factory approved belts.
To change or replace the deck belt on your tractor, proceed asfollows:
1. Lower the deck by moving the deck lift lever into the
bottom notch on the right fender.
2. Remove the belt guards by removing the self-tapping
screws that fasten them to the deck.
3. Remove the belt keeper rod from around the engine pulley.
4. On the 42-inch deck only, loosen but do not remove, the
idler pulley nuts. This will enable the belt to be easily
removed from the idler pulleys. See Fig. 7-6.
WARNING! Avoid the possibility of a pinching
injury. Do not place your fingers on the idler spring
or between the belt and a pulley while removing the
belt.
5. Remove the deck belt from around all pulleys, including
the deck idler pulley.
S_CTION 7-- S_RVlC_ I 25