MTD 504 - Page 19

3. If the blade or blade adapter needs replacing,
remove the two small bolts, lock washers and nuts
which hold the blade to the adapter. See figure 31.
B. Sharpening
Remove the cutting blade by following the directions
of the preceding section.
When sharpening the blade, follow the original angle
of grind as a guide. It is extremely important that each
cutting edge receives an equal amount of grinding to
prevent an unbalanced blade. An unbalanced blade will
cause excessive vibration when rotating at high speeds,
may cause damage to the mower and could break,
causing personal injury.
The blade can be tested for balance by balancing it on
a round shaft screwdriver. Remove metal from the
heavy side until it balances evenly.
NOTE
It is recommended that the blade
always be removed from the adapter
for the best test of balance.
C. Reassembly
Before reassembling the blade and the blade adapter
to the unit, lubricate the spindle and the inner surface
of the blade adapter with light oil. Lubricating the bolt
holes, bolts and inner surface of the nuts with light oil
is also recommended. A 4 oz. plastic bottle of light oil
lubricant is available. Order part number 737-0170.
Engine oil may also be used.
When replacing the blade, 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.
Blade Mounting Torque
3/8" Dia. Bolt 375 in. lb. min., 450 in. lb. max.
5/16" Dia. Bolt 150 in. lb. min., 250 in. lb. max.
NOTE
To insure safe operation, ALL nuts
and bolts must be checked periodi¬
cally for correct tightness.
FUEL FILTER
Your unit is equipped with a replaceable in-line fuel
filter. Replace filter whenever contamination or
discoloration is noticed. Order replacement filter
through your engine authorized service dealer.
CLEANING ENGINE AND BLADE HOUSING
Any fuel or oil spilled on the machine should be wiped
off promptly. Grass, leaves, and other dirt must not be
left to accumulate around the cooling fins of the engine
or on any part of the machine.
Clean the underside of the blade housing after each
mowing.
BELTS
Check that belts are free of oil or dirt. Wipe the belts
periodically with a clean rag.
ENGINE
Refer to separate engine manual for all engine
maintenance instructions.
Maintain engine oil as instructed in the separate
engine manual packed with your unit. Read and follow
instructions carefully.
Service air cleaner every 25 hours under normal con¬
ditions. Clean every few hours under extremely dusty
conditions. Poor engine performance and flooding
usually indicates that the air cleaner should be
serviced.
The spark plug should be cleaned and the gap reset
once a season. Spark plug replacement is recom¬
mended at the start of each mowing season; check
engine manual for correct plug type and gap
specification.
BATTERY MAINTENANCE
1. Check periodically (every two weeks or before and
after charging) to be sure electrolyte level is above
the lowest line on battery. Add only distilled water
or good quality drinking water. NEVER add addi¬
tional acid or other chemicals to battery after ini¬
tial activation.
2. The battery should be checked with a hydrometer
after every 25 hours of operation. If the specific
gravity is less than 1.225, remove battery and
recharge.
3. Coat the terminals and exposed wiring with a thin
coat of grease or petroleum jelly for longer service
and protection against electrolyte corrosion.
4. The battery should be kept clean. Any deposits of
acid should be neutralized with soda and water.
Be careful not to get this solution in the cells.
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