Adjusting Carburetor - Craftsman 247.775890 Owner's Manual

Pipe
Weld Bolt
Allen
Screw
When reassembling the blade, tighten center
bolt to between 550-700 inch-pounds and the
two outer bolts to 250-300 inch-pounds, or
lacking torque wrench, tighten securely.
1. Insert screw driver through hole
"-,,.p
2. Blade should be parallel to ground
Sc
D:d_e_ Blade
I I-
Ground
Torque Wrench
Figure 20
• Remove the six hex lock nuts and lock washers
from the housing weld bolts using a 112"wrench.
Separate the chipper-shredder into two halves.
• Remove the back-up plate,
NOTE: When reassembling, make certain the
embossed tab faces inward towards the impeller, and
opening on the back-up plate is toward the bottom of
the unit.
• Remove the two hand knobs and cupped
washers which secure the chute deflector. Raise
the chute deflector,
• Insert a 112"or 314"diameter pipe through the
flail screen into the impeller to keep it from
turning, or remove the flail screen and insert a
piece of wood (2 x 4) into the chute opening.
• Remove the two outside screws on the blade,
using a 3116"allen wrench and a 1/2" wrench,
• Remove the blade by removing the center bolt,
lock washer and flat washer.
WARNING: Use caution when removing
the blade to avoid contacting the weld bolts
on the housing.
When sharpening the blade, follow the odginal
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 unbalanced blade will cause excessive
vibration when rotating at high speeds and may
cause damage to the unit.The blade can be tested
for balance by balancing iton a round shaft
screwdriveror nail. Remove metal from the heavy
side untilitis balanced evenly. See Figure 21.
Figure 21
Adjusting Carburetor
WARNING: If any adjustments are made to
the engine while the engine is running (e.g.
carburetor), keep clear of all moving parts.
Be careful of heated surfaces and muffler.
Differences in fuel, temperature, altitude or load may
require minor adjustments to the carburetor. This
carburetor is equipped with an idle mixture valve with
a limiter and an idle speed adjustment screw.
• Start engine and let it run for about 5 minutes.
• Rotate carburetor throttle lever against the idle
speed screw and hold it. Turn idle speed screw
to obtain 1750 rpm. See Figure 22.
Carburetor Idle Speed Screw
Thro_ Lever
@
Figure 22
Rotate idle mixture valve full travel clockwise
and then counter-clockwise. Finally position idle
mixture valve in middle of treveL See Figure 22.
16