MTD 520 Series ユーザーズマニュアル
11
5
Maintaining
Your Lawn
Mower
WARNING
When removing
the cutting blade
for sharpening or
replacement or
when sliding the belt
around it, protect
your hands with a
pair of heavy gloves
or use a heavy rag to
hold the blade.
An unbalanced blade
will cause excessive
vibration when rotat-
ing at high speeds. It
may cause damage
to mower, and could
break causing per-
sonal injury.
Blade Care
WARNING: When removing cutting
blade for sharpening or replacement,
protect your hands with a pair of heavy
gloves or use a heavy rag to hold blade.
blade for sharpening or replacement,
protect your hands with a pair of heavy
gloves or use a heavy rag to hold blade.
1. Disconnect spark plug wire from spark plug. Turn
mower on its side making sure that the air filter and
the carburetor are up.
the carburetor are up.
2. Remove bolt, bell washer, blade, and blade adapter
from the engine crankshaft. See Figure 5-2.
3. The blade can be sharpened with a file or on a grind-
ing wheel. Do not attempt to sharpen the blade while
it is still on the mower. When sharpening blade, follow
original angle of grind. Grind cutting edges equally to
keep blade balanced.
it is still on the mower. When sharpening blade, follow
original angle of grind. Grind cutting edges equally to
keep blade balanced.
4. Remove blade from the adapter for testing balance.
Balance the blade on a round shaft screwdriver to
check. Remove metal from the heavy side until it
balances evenly.
check. Remove metal from the heavy side until it
balances evenly.
WARNING: An unbalanced blade will
cause excessive vibration when rotating
at high speeds. It may cause damage
to mower, and could break causing
personal injury.
cause excessive vibration when rotating
at high speeds. It may cause damage
to mower, and could break causing
personal injury.
5. Lubricate the engine crankshaft and the inner surface
of the blade adapter with light oil. Slide the blade
adapter onto the engine crankshaft. Place the blade
on the adapter such that the side of the blade marked
“Bottom” (or with part number) faces the ground when
the mower is in the operating position. Make sure that
blade is aligned and seated on blade adapter flanges.
adapter onto the engine crankshaft. Place the blade
on the adapter such that the side of the blade marked
“Bottom” (or with part number) faces the ground when
the mower is in the operating position. Make sure that
blade is aligned and seated on blade adapter flanges.
6. Place bell washer on the blade. Replace hex bolt and
tighten hex bolt to torque: 450 in. lbs. min., 600 in. lbs.
max.
max.
To ensure safe operation of your mower, periodically
check the blade bolt for correct torque.
check the blade bolt for correct torque.
Belt Care
1. Remove the front drive cover by sliding off the
two plastic rivets on each side of the cover with a
screwdriver. See Figure 5-3.
screwdriver. See Figure 5-3.
2. Disconnect belt tension spring from transmission. See
Figure 5-3.
3. Push transmission up a little and slide belt off the
transmission pulley. Lift mower to access belt from
underside of mower. Slide belt off of engine pulley and
around the blade. See Figure 5-4.
underside of mower. Slide belt off of engine pulley and
around the blade. See Figure 5-4.
4. Replace with new belt, working around blade. Make
sure belt is firmly seated on engine pulley while
pulling from the other side and sliding it around the
transmission pulley. Secure belt tension spring to the
transmission. Reassemble front drive cover.
pulling from the other side and sliding it around the
transmission pulley. Secure belt tension spring to the
transmission. Reassemble front drive cover.
Figure 5-2
Figure 5-3
Figure 5-4