MTD 645B thru 651B - Manual (Page 8)

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mended at the start of each season; check engine
manual for correct plug type and gap specifications.
Clean the engine regularly with a cloth or brush.
Keep the cooling system (blower housing area) clean
to permit proper air circulation which is esse ntial to
engine performance and life. Be certain to remove all
dirt and combustible debris from muffler area.
CLEANING
The shredder may be cleaned by running water from
a hose through the hopper assembly and chipper
chute with the engine running. Allow the shredder to
dry thoroughly.
Wash the bag periodically with water. Allow to dry
thoroughly in the shade. Do not use heat.
REMOVING THE FLAIL SCREEN
If the discharge area becomes clogged, rem we the
flail screen and clean area as follows.
1. Stop the engine, make certain the shred ter has
come to a complete stop and disconnect spark
plug wire from the spark plug before unc logging
the chute.
2. Loosen the two hand knobs on each side of the
chute deflector. Lift the chute deflector up, and tie
it out of the way.
3. Remove two hairpin clips from the cle'ts pins
which extend through the housing. Rem3ve the
clevis pins. Lift the flail screen from inside the
housing. See figure 14.
4. Clean the screen by scraping or washing with
water. Reinstall the screen.
NOTE: Be certain to reassemble the flail screen with
the curved side down as shown in figure 14.
Chute Deflector
SHARPENING OR REPLACING CHIPPER BLADES
1. Disconnect spark plug wire and move it away
from spark plug.
2. Remove the flail screen as instructed in previous
section.
3. Remove the chipper chute by removing three hex
nuts and washers. A 1/2" wrench is required. See
figure 14.
NOTE: When reassembling, the cupped washer goes
on the bottom of the chipper chute with the cupped
side against the chute.
4. Rotate the impeller assembly by hand until you
locate one of the chipper blades in the chipper
chute opening. Remove the blade, using a 3/16"
alien wrench on the outside of the blade and 1/2"
wrench on the impeller assembly (inside the
housing). See figure 15.
5. Remove the other blade in the same manner.
Hand Knobs
FIGURE 14.
FIGURE 15.
Replace or sharpen blades. If sharpening, make cer­
tain to remove an equal amount from each blade.
Reassemble in reverse order.
Make certain blades are reassembled with the sharp
edge facing the direction shown in figure 15 (sharp
edge is assembled toward the slotted opening in the
impeller assembly).
SHARPENING OR REPLACING SHREDDING BLADE
The shredding blade may be removed for sharpening
or replacement as follows.
1. Disconnect spark plug wire and move it away
from spark plug.
2. Lower the leaf ramp. Block up the housing. See
figure 16.
3. Remove the six hex lock nuts and lock washers
from the housing weld bolts using a 1/2" wrench.
Separate the shredder into two halves.
4. Remove the back-up plate.