Bolens 120-337A - Manual (Page 12)

d. Final adjustment of the needle valve
should be slightly to the rich side (turn
counterclockwise) of the mid-point.
3. Move engine control to SLOW. Turn idle ad­
justing screw until a fast idle is obtained (1750
R.P.M.).
4. To check adjustment, move engine control
from SLOW to FAST speed. Engine should ac­
celerate smoothly. If engine tends to stall or
die out, increase idle speed or readjust car­
buretor, usually to a slightly richer mixture.
LUBRICATION
IMPORTANT
Always stop engine and disconnect
spark plug wire before cleaning,
lubricating or doing any kind of work
on lawn mower.
Wheels— Wheel bearings are of self-lubricating For-
tiflex. They require no lubrication.
Engine— Follow engine manual for lubrication in­
structions.
Throttle— Periodically lubricate throttle control
lever and throttle wire assembly with a few drops
of light oil (SAE No. 10 or 20) for ease of operation.
Chain— To lubricate the chain, remove the master
link and chain. Soak the chain in kerosene or a sol­
vent, and let it air dry. Wipe the chain with a rag
saturated with SAE 30 oil. Reassemble the chain
to the sprockets. Closed end of the master link
clip should face in direction of chain travel.
If the rotary mower is operated in a sandy area, the
chain should not be lubricated. Excessive oil on a
chain will collect dirt and cause excessive wear
on the chain and sprockets.
Discharge Chute Door Mechanism— The torsion
spring and pivot point should be lubricated
periodically with light oiMo prevent any rust or
binding. Door must work freely.
MAINTENANCE
CUTTING BLADE
The blade may easily be removed for sharpening
or replacement as follows:
1. Remove the center bolt and center lock
washer holding the blade and adapter to the
engine crankshaft.
2. Remove the blade and adapter from the
crankshaft.
3. Be careful not to lose the key on the
crankshaft. See figure 25.
4. Remove the two smaller bolts, lock washers
and nuts holding the blade to the adapter. See
figure 25.
When sharpening blade, follow the original angle
of grind as a guide. It is extremely important that
each cutting edge receives an equal amount of
grinding to prevent an unbalanced blade. An un­
balanced blade will cause excessive vibration
when rotating at high speeds and may cause
damage to the mower.
The blade can be tested for balance by balancing
it on a screw driver. Remove metal from the heavy
side until it balances evenly. See figure 26.
12