Echo 72854s - Manual (Page 21)

17
Service and
Maintenance
Warning: Before inspecting or servicing any
part of the machine, shut off the engine, and
make sure all moving parts have come to a complete
stop. The chipping blades are sharp! Use care when
working on machine to avoid injury.
Warning: The rotor assembly has a lock
mechanism. When working on the rotor
assembly, use the lock mechanism at all times.
Remove the plastic bearing cover beside the chipper
chute. There is a hole in the rotor shaft and a match-
ing hole in the bracket mounted to the rotor bearing
front side. Install a punch through the rotor shaft and
bracket to lock the rotor in place.
On engine models, check the engine oil, and change
the oil and filter as recommended in the manual.
Service and replace the air cleaner as recommended.
5.3 Sharpening Chipper Blades
The chipper blades will eventually become dull,
making chipping difficult. It is recommended that
the chipper blades are sharpened every 5-15 hours
of chipper operation. To remove the chipping blades
for sharpening:
1. Remove the two 3/8 inch retaining bolts holding
access cover to main frame assembly.
2. Tilt access cover over to allow rotor access.
Rotate the rotor so that the bolts holding a
chipping blade are most accessible.
3. Remove the two allen head bolts holding the
blade itself. Repeat for all four blades. The four
chipping blades have two edges per blade and
can be reversed one time each before sharpen-
ing. If both sides have not been used, remove
and reverse the chipping blades. Reinstall chip-
ping blades and proceed with chipping.
To grind the angled edge of the chipping blade to 45
degrees (see figure 10.15): Grind the blades on a
slow-speed wet grinder if possible, or have them
sharpened by a professional. If you use a bench
grinder, be careful when grinding so that the blade
material does not get too hot and change color–this
will remove the blade's special heat treated
properties. Use short grinding times and cool with
water. Try to remove an equal amount off each blade
to maintain balance. Replace the chipping blades and
tighten bolts to 75 ft. lbs. Close cover and replace bolts.
5.4 Chipping Blade Sharpening Tips
Poor chipping performance is usually a result of dull
chipping blades. If your chipper's performance has
decreased, check for the following symptoms:
• Severe vibration when feeding material into the
chipper.
• Small diameter branches do not self-feed.
• Chips discharge unevenly or have stringy tails–
especially when chipping green branches.
Before you sharpen the chipping blades, check for
permanent damage. Replace the blade if:
• The blade is cracked (especially around the bolt
holes) or the edges are too deeply chipped to be
ground smooth.
• The base of the cutting edge is worn or has been
re-sharpened so that it is too close to the rotor
chipping slot.
5.5 Setting Chipping Blade Clearance
The four chipping blades should clear the chipper
anvil located directly under the chipper chute by
1/16 inch to 1/8 inch. The chipper anvil is adjustable
and reversible.
To adjust:
1. Lift rotor access cover and expose rotor (see
figure 10.16). Loosen the three 1/2 inch bolts
that hold the chipper anvil to the frame (see
figure 10.17).
2. Measure the amount of clearance between
chipping blade and chipper anvil from inside of
housing.
3. Adjust inward or outward to desired measure-
ment.
4. Tighten bolts on chipping block to 75 ft. lbs. and
resume operation.
If chipper anvil edge is damaged or worn unevenly,
remove the three bolts holding the anvil and use one
S E C T I O N 5