20
Note:
The blade will remain balanced if you remove the
same amount of material from both cutting edges.
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. 25).
1007
Figure 25
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. Install a sharp, balanced Lawn-Boy blade and the
blade nut. See Figure 23.
Note:
The sail part of the blade must point toward the top
of the lawn mower housing for proper installation.
2. Tighten the blade nut to 47 ft-lb (63 N
⋅
m).
3. Connect the wire to the spark plug.
Note: Replace the blade nut after installing and removing
it four times. The locking feature of the blade nut
decreases and could loosen if you do not replace it.
Servicing the Air Filter
Clean the air filter once every season or every 50
operating hours; clean it more frequently under dusty
conditions.
IMPORTANT: Do not operate the engine without the
air filter element; extreme engine damage will occur.
1. Remove the cover o-ring rubber from the cover hook
and remove the air filter cover (Fig. 26).
m-4820
1
2
3
4
Figure 26
1.
Air filter cover
2.
Air filter
3.
Cover hook
4.
O-ring rubber
2. Remove the air filter.
3. Wash the air filter in laundry detergent or kerosene
(Fig. 27).
988
Figure 27
4. Squeeze the air filter to remove excess liquid and blot
it dry with a paper towel or rag.
5. Allow the air filter to thoroughly dry.
6. Saturate the air filter with SAE 30W oil (Fig. 28).
989
Figure 28
7. Squeeze the air filter to distribute the oil evenly. Blot
the air filter lightly with a paper towel to remove
excess oil.
8. Replace the air filter with the cleanest side facing the
carburetor.
Note:
Ensure that the filter fully seats in the air box and
does not pucker, allowing air and dirt to pass directly
through to the carburetor.
9. Install the air filter cover (Fig. 26).
