Husqvarna 51 - Manual (Page 10)

CUSTOMER RESPONSIBILITIES
10
LAWN MOWER
Always observe safety rules when performing any mainte-
nance.
TIRES
• Keep tires free of gasoline, oil, or insect control chemi-
cals which can harm rubber.
• Avoid stumps, stones, deep ruts, sharp objects and
other hazards that may cause tire damage.
BLADE CARE
For best results, mower blade must be kept sharp. Re-
place bent or damaged blades.
TO REPLACE BLADE (See Fig. 11)
• Turn lawn mower on its side. Make sure air filter and
carburetor are up.
• Use a wood block between blade and mower housing
to prevent blade from turning when removing blade
bolt.
• Protect your hands with gloves and/or wrap blade with
heavy cloth.
• Remove blade bolt, lock washer and flat washer.
• Remove blade and blade adapter.
• Inspect the key inside blade adapter. Replace adapter
if damaged.
IMPORTANT: BLADE BOLT IS GRADE 8 HEAT TREATED.
• Install new or sharpened blade with trailing edge up
toward the engine.
• Position blade on blade adapter. Align the two (2)
holes in blade with raised lugs of adapter.
• Reassemble blade bolt, lock washer and flat washer
into blade adapter and crankshaft in exact order as
shown.
• Position block of wood between blade and mower
housing.
• Tighten blade bolt securely. Recommended tightening
torque is 35-40 ft. lbs.
NOTE: We do not recommend sharpening blade - but if
you do, be sure the blade is balanced.
FIG. 11
BLADE
TRAILING EDGE
CRANK-
SHAFT
LOCK
WASHER
FLAT STEEL
WASHER
KEY
BLADE
BOLT
BLADE ADAPTER
TO SHARPEN BLADE
Care should be taken to keep the blade balanced. An
unbalanced blade will cause excessive vibration and even-
tual damage to lawn mower and engine.
•
The blade can be sharpened with a file or on a grinding
wheel. Do not attempt to sharpen while on the mower.
• To check blade balance, drive a nail into a beam or wall.
Leave about one inch of the straight nail exposed.
Place center hole of blade over the head of the nail. If
blade is balanced, it should remain in a horizontal
position. If either end of the blade moves downward,
sharpen the heavy end until the blade is balanced.