Blade Care - MTD 21 Operator's Manual

Wheels
• The wheels require no lubrication. However, if the
wheels are removed for any reason, lubricate the
surface of the axle bolt and the inner surface of the
wheel with light oil. Engine oil may also be used.
When tipping the unit, empty the fuel tank and keep
engine spark plug side up.
Lube
Figure 13 : Lubrication Chart

Blade Care

• Periodically inspect the blade adapter for cracks,
especially if you strike a foreign object. Replace
when necessary.
WARNING:
blade for sharpening or replacement, protect
hands by using heavy gloves or a rag to grasp
the cutting blade.
To remove blade
• Remove the bolt and blade support or bell washer
which hold the blade and adapter to the engine
crankshaft. See Figure 14. Remove the blade and
adapter from the crankshaft.
Blade Adapter
Blade
Figure 14
When removing the cutting
Blade
Bell
Support
Hex Bolt
To balance blade
• When sharpening the blade, follow original angle of
grind as a guide. It is extremely important to grind
off all edges equally to keep the blade balanced.
NOTE: An unbalanced blade will cause excessive
vibration when rotating at high speeds and may cause
damage to the mower and/or personal injury.
• Test the blade by balancing it on a round shaft
screwdriver. See Figure 15.
• Remove metal from the heavy side until it balances
evenly. Always remove blade from the adapter for
the best test of balance.
1. Insert screw driver through hole
2. Blade should be parallel to ground
Screw
Driver
To reassemble blade
• Lubricate the engine crankshaft and the inner
surface of the blade adapter with light oil (or engine
oil). Also lubricate the bolt holes, bolts and inner
surface of the nuts.
• Install the blade adapter on the crankshaft with the
"star" away from the engine. Refer to Figure 14.
Place the blade with the side marked bottom (or
with part number) facing away from the adapter.
• Align the blade bell support over the blade with the
tabs in the holes of the blade and insert the hex
bolt. Tighten the hex bolt to the torque listed in the
"Blade Mounting Torque" section below.
Blade Mounting Torque
Center Bolt: 450 in. lbs. min., 600 in. lbs. max.
To ensure safe operation, all nuts and
IMPORTANT:
bolts must be checked periodically for correct tightness.
Replacing Rear Flap
• To remove rear flap, compress the hinge clips and
remove from the slots in rear of deck.
• Attach new rear flap by placing new spring clips in
the slots on the flap. Then compress the spring
clips and reinsert in slots in rear of deck.
Engine
• Follow engine manual for instruction and schedule
of maintenance and lubrication.
12
Blade
Ground
Figure 15