Blade Care; Lawn Mower - Husqvarna HU550FH / 961430096 Operator's Manual

LAWN MOWER

Always observe safety rules when performing any main-
te nance.
TIRES
• Keep tires free of gasoline, oil, or insect control chem i-
cals which can harm rubber.
• Avoid stumps, stones, deep ruts, sharp objects and
other hazards that may cause tire damage.
DRIVE WHEELS
Check front drive wheels each time be fore you mow to be
sure they move freely.
The wheels not turning freely means trash, grass cuttings,
etc. are in the drive wheel area and must be cleaned to
free drive wheels.
If necessary to clean the drive wheels, be sure to clean
both front wheels.
1. Remove hubcaps, locknuts and washers.
2. Remove wheels from wheel ad just ers.
3. Remove any trash or grass cuttings from inside the
dust cover, pinion and/or drive wheel gear teeth.
4. Put wheels back in place.
NOTE: If after cleaning, the drive wheels do not turn freely,
contact a qualified service center.

BLADE CARE

For best results, mower blade must be kept sharp. Re place
bent or dam aged blades.
CAUTION:
blade approved by the manufacturer of
your mower. Using a blade not approved
by the manufacturer of your mower is
hazardous, could damage your mower
and void your warranty.
TO REMOVE BLADE (See Fig. 13)
1. Disconnect spark plug wire from spark plug and place
wire where it cannot come in contact with plug.
2. Turn lawn mower on its side. Make sure air filter and
carburetor are up.
3. Use a wood block between blade and mower hous ing
to prevent blade from turning when re mov ing blade
bolt.
NOTE: Protect your hands with gloves and/or wrap blade
with heavy cloth.
4. Remove blade bolt by turning counter-clockwise.
5. Remove blade and attaching hardware (bolt, lock
wash er and hardened wash er).
NOTE: Remove the blade adapter and check the key inside
hub of blade adapter. The key must be in good condition
to work properly. Replace adapter if damaged.
TO REPLACE BLADE (See Fig. 13)
1. Position the blade adapter on the engine crank shaft.
Be sure key in adapter and crankshaft keyway are
aligned.
MAINTENANCE
Use only a replacement
2. Position blade on the blade adapter.
IMPORTANT: TO ENSURE PROPER AS SEM BLY, CENTER HOLE
IN BLADE MUST ALIGN WITH STAR ON BLADE ADAPTER.
3. Be sure the trailing edge of blade (opposite sharp
edge) is up toward the engine.
4. Install the blade bolt with the lock washer and hardened
washer into blade adapter and crankshaft.
5. Use block of wood between blade and lawn mower
housing and tighten the blade bolt, turning clockwise.
• The recommended tightening torque is 35–40 ft. lbs.
(47–54 Nm).
IMPORTANT: BLADE BOLT IS HEAT TREATED. IF BOLT NEEDS
REPLACING, REPLACE ONLY WITH APPROVED BOLT.
BLADE ADAPTER
BLADE
LOCK
WASHER
BLADE
HARDENED
BOLT WASHER
TRAILING EDGE
TO SHARPEN BLADE (See Fig. 14)
NOTE: We do not recommend sharp en ing blade - but if
you do, be sure the blade is balanced. An un bal anced
blade will cause eventual damage to lawn mower or engine.
• The blade can be sharp ened with a file or on a grinding
wheel. Do not attempt to sharpen while on the mower.
• To check blade balance, you will need a 5/8" diameter
steel bolt, pin, or a cone balancer. (When using a
cone bal anc er, follow the in struc tions supplied with
bal anc er.)
NOTE: Do not use a nail for balancing blade. The lobes
of the center hole may appear to be centered, but are not.
• Slide blade on to an unthreaded portion of the steel
bolt or pin and hold the bolt or pin parallel with the
ground. If blade is bal anced, it should remain in a
horizontal po si tion. If either end of the blade moves
downward, sharpen the heavy end until the blade is
balanced.
CENTER HOLE
5/8" BOLT OR PIN
12
KEY CRANKSHAFT
CRANKSHAFT
FIG. 13
BLADE
FIG. 14
KEY WAY
BELT
RETAINER