SECTION 7: SERVICING YOUR MOWER

Blade Care

Periodically inspect the blade adapter and pulley for cracks, especially if you strike a foreign object. Replace when necessary.

WARNING: When removing the cutting blade for sharpening or replacement, protect hands by using heavy gloves or a thick rag to grasp the cutting blade.

Disconnect spark plug wire from spark plug.

Turn mower on its side making sure that the air filter and the carburetor are up.

Remove the bolt and blade support or bell washer which hold the blade and adapter to the engine crankshaft. See Figure 13. Remove the blade and adapter from the crankshaft.

Blade Adapter

Blade

Blade

Bell

Support

Hex Bolt

Figure 13

To Sharpen Blade:

The blade can be sharpened with a file or on a grinding wheel. Do not attempt to sharpen the blade while it is still on the mower.

Follow the original angle of grind as a guide. Make sure that each cutting edge receives an equal amount of grinding to prevent an unbalanced blade.

NOTE: 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 by balancing it on a round shaft screwdriver. See Figure 14. Remove metal from the heavy side until it balances evenly. It is recommended that the blade always be removed from the adapter for the best test of balance.

1.Insert screw driver through hole

2.Blade should be parallel to ground

Screw

 

 

 

 

 

Blade

 

 

 

 

 

Driver

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ground

Figure 14

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 (or engine oil). Also lubricate the bolt holes, bolts and inner surface of the nuts.

Install the blade adapter on the crankshaft with the “star” away from the engine. Refer to Figure 13. 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 center bolt to 450 in. lbs. min., 600 in. lbs. max.

IMPORTANT:To ensure safe operation, all nuts and bolts must be checked periodically for correct tightness.

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MTD Series 430 Thru 439 manual Servicing Your Mower, Blade Care, To Sharpen Blade