MTD YARD MACHINES 070 Series Owner's Manual page 11

crankshaft. Remove the blade and adapter from
the crankshaft.
NOTE: If the blade is secured to the blade adapter with
two bolts, remove the two small bolts, lock washers and
nuts which hold the blade to the adapter.
WARNING: Periodically inspect the
blade adapter for cracks, especially if
you strike a foreign object. Replace when
necessary.
a. Sharpening Blade:
• Follow the original angle of grind as a guide. Make
sure that each cutting edge receives an equal
amount of grinding to prevent an unbalanced
blade.
NOTE: An unbalanced blade will cause excessive
vibration when rotating at high speeds, may cause
damage to the mower and could break, causing
personal injury.
•
Test the blade 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 for the best test of
balance.
• Before reassembling the blade and the blade
adapter to the unit, lubricate the engine crankshaft
and the inner surface of the blade adapter with light
oil (or engine oil). Lubricating the bolt holes, bolts
and inner surface of the nuts is also recommended.
b. Replacing Blade:
THREE BOLT BLADE MOUNTING:
• Install the blade to the blade adapter with the side
of the blade marked "bottom" (or with part number)
facing away from the adapter. See figure 12.
Insert two hex bolts up through the blade and adapter
and secure with lock washers and hex nuts.
Tighten according to the blade mounting torque
mentioned below.
• Place the blade and the blade adapter assembly on
the engine crankshaft.
NOTE: If the adapter is keyed, make sure that the key in
the adapter is aligned with the key slot on the
crankshaft.
•
Place the bell washer on the hex nut with the
crowned side of the bell washer against the head of
the bolt. See figure 12.
• Insert the hex bolt and bell washer assembly
through the blade and blade adapter assembly.
• Tighten the hex bolt according to the blade
mounting torque mentioned below.
SINGLE BOLT BLADE MOUNTING
• Install the blade adapter on the crankshaft with the
"star" away from the engine. See figure 13.
• Place the blade with the side marked bottom (or
with part number) facing away from the adapter.
• Place the blade bell support over the blade aligning
the tabs in the holes of the blade with the hole in the
Blade Adapter
Figure 13
bell support and insert the hex bolt.
• Tighten the hex bolt according to the blade
mounting torque mentioned below.
BLADE MOUNTING TORQUE
Center Bolt: 450 in. lbs. min., 600 in. lbs. max.;
Blade Adapter Bolts (if applicable): 200 in. lbs. min., 350
in. lbs. max.
To ensure safe operation of your unit, all nuts and bolts
must be checked periodically for correct tightness.
2. DECK
The underside of the mower deck should be cleaned
after each use to prevent a buildup of grass clippings,
leaves, dirt or other matter. If this debris is allowed to
accumulate, it will invite rust and corrosion, and may
cause an uneven discharge of grass clippings at the
next cutting.
The deck may be cleaned by tilting the mower and
scraping clean with a suitable tool (make certain the
spark plug wire is disconnected).
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