11
Section 4 - REPAIR & ADJUSTMENTS
WARNING
Before attempting any adjustments or repairs, STOP
the engine, remove the spark plug wire from the
spark plug and secure wire away from plug. Wear
heavy leather gloves when handling or working
around cutting blades. Blades are extremely sharp
and can cause severe injury.
4.1 MOWER BLADE REPAIR/REPLACEMENT
4.1.1. STANDARD BLADE WEAR LIMIT
1. Inspect blade frequently for signs of excessive wear
or damage. See Figure 4.1.
FIGURE 4.1
4.1.1A. NINJA BLADE WEAR LIMIT
1A. Inspect blade frequently for signs of excessive
wear or damage. See Figure 4.1A.
FIGURE 4.1A
2. Replace the blade if it is badly chipped, bent,
noticeably out of balance or has cracks or notch in
either tip. See Figure 4.1 & 4.1A. Replace with new
blade.
WARNING
Never use a cutting blade that shows signs of
excessive wear or damage. Refer to Section on
MOWER BLADE REPAIR/REPLACEMENT for proper
blade inspection and service procedures.
4.1.2. BLADE SHARPENING
1. Disconnect spark plug wire and secure end away
from plug.
2. Tilt mower up on its rear wheels. Do not tilt
mower with spark plug or carburetor down.
3. Remove blade. See Figure 4.2.
FIGURE 4.2
4. Sharpen blade on a grinding wheel at an angle of
22 to 28 degrees. DO NOT sharpen blade beyond
original cutting edge. See Figure 4.3.
FIGURE 4.3
5. Check blade for balance. If necessary, correct
balance by grinding heavy end of blade.
6. Reinstall blade. Refer to Figure 4.1. Check torque
of blade retaining cap screw. Recommended torque
should be 30 to 40 ft. lbs.
NEW BLADE
WEAR LIMIT
(NOTCH STARTS)
DANGEROUS
CONDITION !
DO NOT USE ON
MOWER !
REPLACE WITH NEW
BLADE.
NEW BLADE
WEAR LIMIT.
CRACKS OR
NOTCHES
BEGIN TO
APPEAR ON TIP
DANGEROUS !
DO NOT USE A BLADE IN
THIS CONDITION !
BLADE
HUB
MAKE SURE THAT
BLADE HUB IS
SEATED
BETWEEN
FLANGES
FLANGE
BLADE
CONE WASHER
(Concave Side Up)
CAPSCREW
DO NOT SHARPEN
BEYOND
ORIGINAL
CUTTING EDGE
22-28º
BLADE TIP
END VIEW OF
BLADE ASSEMBLY
ORIGINAL CUTTING EDGE