Servicing Your Lawn Mower - Yard-Man 978Q Operator's Manual

SECTION 8: SERVICING YOUR LAWNMOWER
WARNING: Always stop the engine and
disconnect the spark plug wire before
performing any maintenance work or
adjustments on your lawn mower.
BladeCare
WARNING: 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.
Periodically inspect the blade adapter for cracks,
especially if you strike a foreign object. Replace when
necessary.
Removingthe Blade
• Disconnect spark plug wire from spark plug.
• Turn mower on its side making sure that the air filter
and the carburetor are up.
• Remove the bolt and the blade bell support which
hold the blade and the blade adapter to the engine
crankshaft. See Figure 17.
• Remove the blade and the adapter from the
crankshaft.
Sharpening t heBlade
• The blade can be sharpened with a file or on a
grinding wheel. Do not attempt to sharpen the
blade while it is still on the mower.
• 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.
_b ARNING" 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.
Balancingthe Blade
• 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.
Installingthe Blade
• Before reinstalling the blade and the blade adapter
to the unit, lubricate 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 onto the engine crankshaft.
• Place the blade on the adapter. Be certain the
blade is aligned 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
small holes in the blade.
• Replace hex bolt and tighten hex bolt to torque: 450
in. Ibs. min., 600 in. Ibs. max.
NOTE: To ensure safe operation of your mower,
3eriodically check the blade bolt for correct torque.
Blade
Adapter---_
Bolt
Figure 17
DriveBeltReplacement
• Disconnect the spark plug wire and ground it
against the engine.
• Drain the fuel tank or place a piece of plastic
beneath the cap to prevent gasoline leakage.
• Place shift lever in the first position and tip the
mower on its side with air filter facing up.
• Remove the center bolt which secures the blade to
the crankshaft followed by blade bell support,
blade, and blade adapter.
• Move the cutting height adjustment to the highest
position.
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