17
Note: Do not grind the blade more than 5 in. (127 mm)
from the outside ends and no less than 2 in. (51 mm) from
the trailing edge (Fig. 27).
990
2”
(51 mm)
5”
(127 mm)
Figure 27
Balancing the Blade
1. Check the balance of the blade by placing the center
hole of the blade over a nail or a screwdriver shank
clamped horizontally in a vise (Fig. 28).
1007
Figure 28
Note: You can also check the balance by using a
commercially manufactured blade balancer.
2. If either end of the blade rotates downward, file that
end (not the cutting edge or the end near the cutting
edge). The blade is properly balanced when neither
end drops.
Installing the Blade
1. Ensure that the blade driver is installed on the
crankshaft. See Figure 25.
2. Install the blade over the lugs of the blade driver with
the curved ends toward the housing (Fig. 25).
3. Install the mulch fan into the blade recess (Fig. 25).
4. Secure the blade with the blade nut (Fig. 25).
5. Torque the blade nut to 47 ft-lb (63 N
m).
Note: Replace the blade nut after installing and removing
the blade four times. The blade nut’s locking power
diminishes and the blade nut could loosen if you do not
replace it.
6. Connect the wire to the spark plug.
Cleaning the Exhaust Port
Carbon deposit build-up causes excessive wear and loss of
power. Check and clean the exhaust port every 100 hours.
1. Disconnect the wire from the spark plug (Fig. 7).
2. Drain the fuel from the fuel tank.
3. Tip the lawn mower onto its right side.
WARNING
POTENTIAL HAZARD
•
Gasoline is extremely flammable, highly
explosive and under certain conditions can
cause personal injury or property damage.
WHAT CAN HAPPEN
•
Tipping the lawn mower may cause fuel leakage
from the carburetor or fuel tank.
HOW TO AVOID THE HAZARD
•
Avoid fuel spills by running the engine dry or
removing the gas with hand pump; never
siphon.
4. Remove the blade nut, mulch fan, and blade. Refer to
Removing the Blade on page 16.
5. Remove the four capscrews that attach the cover plate
to the engine mounting plate (Fig. 29).
m–3836
1
3
2
4
5
Figure 29
1.
Cover plate
2.
Cap screw
3.
Transfer pipe
4.
Exhaust port
5.
High temperature silicone
sealant
6. Remove the transfer pipe (Fig. 29).
7. Inspect the transfer pipe and clean it if it is dirty.
8. Rotate the crankshaft slowly until the piston covers the
exhaust port (Fig. 29).
9. Using a wooden dowel, loosen the carbon deposits by
inserting the dowel into the exhaust port.
Note: Do not use metal tools; they can scratch the piston.
