Craftsman 247.20400 series Operator's Manual page 26

3. 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 25-30° angle. See Figure 32.
4. 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 mower 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.
5. When reinstalling the blades, be sure they are installed so that the wings are
pointing upward toward the top of the deck.
6. Tighten the blade nuts to 70-90 ft. lbs.
7. Reinstall the deck (refer to Deck Installation).
Changing the Transmission Drive Belt
Several components must be removed and special tools used in order to change the
riding mower's transmission drive belt, have your riding mower checked by a Sears
or other qualified service dealer.
Riding Mower Creeping
Creeping is the slight forward or backward movement of the riding mower when
the throttle is on and the speed control levers are in the neutral position. If your
riding mower creeps, have riding mower serviced by a Sears or other qualified
service dealer.
SERVICE AND MAINTENANCE
Figure 32
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