MTD 760, 779, 760-779 warranty Cutting Blades, Maintaining Your Lawn Tractor

Models: 760, 779 760-779

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Cutting Blades

Cutting Blades

WARNING: Be sure to shut the engine off, remove ignition key, disconnect the spark plug wire(s) and ground against the engine to prevent unintended starting before removing the cut- ting blade(s) for sharpening or replacement. Protect your hands by using heavy gloves or a rag to grasp the cutting blade.

WARNING: Periodically inspect the blade spindles for cracks or damage, especially if you strike a foreign object. Replace immedi- ately if damaged.

The blades may be removed as follows.

1.Remove the deck from beneath the tractor, (refer to Cutting Deck Removal on page 23) then gently flip the deck over to expose its underside.

2.Place a block of wood between the center deck hous- ing baffle and the cutting blade to act as a stabilizer. See Figure 24.

3.Use a 15/16” wrench to remove the hex flange nut that secures the blade to the spindle assembly. See Figure 24.

4.To properly sharpen the cutting blades, remove equal amounts of metal from both ends of the blades along the cutting edges, parallel to the trailing edge, at a 25° to 30° angle.

IMPORTANT: If the cutting edge of the blade has already been sharpened to within 1 5/8” from the edge, or if any metal separation is present, replace the blades with new ones. See Figure 25.

It is important that each cutting blade edge be ground equally to maintain proper blade balance.

A poorly balanced blade will cause excessive vibration and may cause damage to the tractor and result in personal injury. The blade can be tested by balancing it on a round shaft screwdriver. Grind metal from the heavy side until it balances evenly.

Figure 24

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Figure 25

When replacing the blade, be sure to install the blade with the side of the blade marked ‘‘Bottom’’ (or with a part number stamped in it) facing the ground when the mower is in the operating position.

IMPORTANT: Use a torque wrench to tighten the blade spindle hex flange nut to between 70 foot-pounds and 90

foot-pounds.

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Maintaining

Your Lawn

Tractor

WARNING

Be sure to shut the engine off, remove ignition key, discon- nect the spark plug wire(s) and ground against the engine to prevent unintended starting before remov- ing the cutting blade(s) for sharpening or replacement. Protect your hands by using heavy gloves or a rag to grasp the cutting blade.

Periodically inspect the blade spindles for cracks or damage, especially if you strike a foreign object. Replace immediately if damaged.

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MTD 760, 779, 760-779 warranty Cutting Blades, Maintaining Your Lawn Tractor