MTD 503 Lawn Mower User Manual


 
12
Blade Care and Replacement
Periodically inspect the blade adapter for cracks,
especially if you strike a foreign object. Replace when
necessary. Follow the steps below for blade service:
Disconnect spark plug wire from spark plug.
Tip mower as specified in separate engine manual. If it
does not specify 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 14.
Remove blade and adapter from the crankshaft.
The blade may be resharpened by removing it and
either grinding or filing the cutting edge keeping as
close to the original bevel as possible. Do not attempt
to sharpen the blade while it is still on the mower.
It is extremely important that each cutting edge receives an equal amount of grinding to prevent an
unbalanced blade.
NOTE: Improper blade balance will result in excessive vibration causing eventual damage to the engine and mower.
Be sure to carefully balance blade after sharpening. Possible damage resulting from blade unbalance condition is
not the responsibility of the manufacturer.
NOTE: Always remove blade from the adapter for testing balance.
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.
Before reassembling the blade and the blade adapter to the unit, lubricate the engine crankshaft and the inner
surface of the blade adapter with light oil.
Install the blade adapter on the crankshaft with the “star” away from the engine. See Figure 14. Place the blade
with the side marked “bottom” (or with part number) facing away from the adapter. Align the blade bell support
over the blade with the tabs in the holes of the blade and insert the hex bolt.
Tighten the hex bolt to the torque listed below:
Blade Mounting Torque
Center Bolt 450 in. lb. min., 600 in.lb. max.
To insure safe operation of your unit, ALL nuts and bolts must be checked periodically for correct tightness.
NOTE: Cutting grass in sandy soil condition causes abrasive wear to the blade.
Off-Season Storage
The following steps should be taken to prepare your lawn mower for storage.
1. Clean and lubricate mower thoroughly as described in the lubrication instructions.
IMPORTANT:
We do not recommend the use of a pressure washer or garden hose to clean your unit.
2. Refer to engine manual for correct engine storage instructions.
3. Coat mower’s cutting blade with chassis grease to prevent rusting.
4. Store mower in a dry, clean area. Do not store next to corrosive materials, such as fertilizer.
NOTE: When storing any type of power equipment in a poorly ventilated or metal storage shed, care should be
taken to rust-proof the equipment. Using a light oil or silicone, coat the equipment, especially cables and all moving
parts of your lawn mower before storage.
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.
Blade
Hex Bolt
Blade Bell
Adapter
Support
Figure 14