Echo 72928 Owners Manual v.2 - Manual (Page 19)

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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 matching 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.
Check the engine oil, and change the oil and filter as
recommended in the manual. Service and replace the air
cleaner as recommended.
3.1 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 re-
versed one time each before sharpening. If both
sides have not been used, remove and reverse the
chipping blades. Reinstall chipping blades and
proceed with chipping.
To grind the angled edge of the chipping blade to 45
degrees (see figure 3.1): 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.
3.1.1 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
Figure 3.2
Service and Maintenance
45 ⋅⋅⋅⋅⋅
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0.38
Sharpening
Edges
Figure 3.1
S E C T I O N 3