Echo 74520 Owners Manual v.1 - Manual (Page 20)

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Check the engine oil, and change the oil and filter as recommended in the engine
manual. Service and replace the air cleaner as recommended.
The chipper blades will eventually dull, making chipping difficult. It is recommended to
sharpen chipper blades every 5-15 hours of chipper operation. To remove the chipping blades
for sharpening:
1. Remove the one 3/8 inch retaining bolt 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 hex head bolts holding the chipper blade. Repeat for all four chipper
blades. The four chipping blades have two edges per blade and can be reversed one time
each before sharpening. Remove and reverse the chipping blades if both sides have not
been used. Reinstall chipping blades and proceed with chipping.
4. To grind the angled edge of the chipping blade to 45 degrees (see figure 2):
• Grind the blades on a slow-speed wet grinder if possible or have them
sharpened by a professional.
Figure 2
Service and Maintenance
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.
Sharpening Chipper Blades