MTD YARD-MAN 970 Owner's Manual page 18

CUTTING BLADE REMOVAL, REPLACEMENT AND SHARPENING
• When removing the cutting blade for sharpening or replacement, protect your hands with a pair of heavy
gloves or use a heavy rag to hold the blade.
• Remove the bolt and the blade bell support which hold the blade and the blade adapter to the engine
crankshaft.
• Remove the blade and the adapter from the crankshaft.
A
WARNING:
Periodically inspect the blade adapter for cracks, especially if you strike a foreign object.
Replace when necessary.
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. An unbalanced blade will
cause excessive vibration when rotating at high speeds. It may cause damage to the mower, and could break
causing personal injury.
The blade can be tested by balancing it on a round shaft screwdriver. Remove metal from the heavy side until it
balances evenly. It is recommended that the blade always be removed from the adapter when testing for balance.
Before reinstalling the blade and the blade adapter to the unit, iubricate the engine crankshaft and the inner
surface of the blade adapter with light oil.
• Be sure to install the blade with the side of the blade marked "Bottom" (or with part number) facing the
ground when the mower is in the operating position.
• Slide the blade adapter on to the engine crankshaft.
• Place the blade on the adapter. Be certain the blade is aligned with and seated on the blade adapter
flanges.
• Place blade bell support on blade. Make sure the notches on the blade bell support are aligned with the
small holes in the blade.
• Replace hex bolt.
• Tighten hex bolt to torque: 450 in. lbs. min., 600 in. lbs. max.
NOTE:
To ensure safe operation of your mower, the blade bolt must be checked periodically for correct torque.
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