Carburetor; Mixture Adjustment; Idle Rpm Adjustment; Checking Adjustment - Craftsman 917.299642 Owner's Manual

IIIlUl II
SERVICE AND ADJUSTMENT
CARBURETOR
NOTE: A dirty Air Cleaner will cause the Engine to run
rough. Be sure Air Cleaner is clean before adjustments_
Factory settings are satisfactory for most applications
and conditions, if adjustments are needed, proceed as
follows:
Never attempt to change maximum Engine speed. This
is preset at the fa,ctory and should only be changed by a
qualified service technician who has the necessary
equipment. The Carburetor mixture may need re-adjust-
ing it Engine lacks power' or does not idle properly,
MIXTURE ADJUSTMENT
. Turn Needle Valve (Fig. 33) clockwise (('_1) until it just
closes. Valve may be damaged by turning Needle Valve
in too far,
• Open Needle Valve 1-1t2 turns counterclockwise (J¢'_),
This initial adjustment will permit the Engine to be
started and warmed up prior to final adjustment,
• Start the Engine,. Allow Engine to warm up for about 5
minutes before proceeding,,
. Place Throttle Control in "iDLE" position,
• Turn Needle Valve in until Engine slows (clockwise
((-_) lean mixture).,
THROTTLE THROTTLE
LINKAGE STOP
* Next turn Needle Valve out past smoothoperatingpoint
until Engine runs unevenly (counterclockwise(F'_) rich
mixture).
, Now turn Needle Valve to the midpoint between rich
and lean so the Engine runs smoothly_
IDLE RPM ADJUSTMENT
• To adjust Idle RPM, Rotate Throttle Linkage counter-
clockwise (V'_,) and hold against stop while adjusting
Idle Speed Adjusting Screw to obtain 1750 RPM. Re-
lease Throttle Linkage,,
CHECKING ADJUSTMENT
. Test the Engine by tilling,If Engine dies out, it usually
indicates that the mixture is slightly lean and it may be
necessary to turn the Needle Valve counterclockwise
(_"_,) slightly to provide a richer mixture,. This richer
mixture may cause a slight unevenness in idling..
THROTTLE CONTROL CABLE ADJUSTMENT
CAUTION; NEVER TAMPER WITH THE ENGINE GOV-
ERNOR, WHICH IS FACTORY SET FOR
PROPER ENGINE SPEED°
• Loosen Throttle Cable Adjusting Screw.
. With Throttle Control in "FAST" position and Cable con-
nected to Bellcrank, pull Cable backward through Screw
until Bellcrank is as far rearward as it will go.
, Tighten Adjusting Screw
MUFFLER ;PARK PLUG
WIRE
IDLE SPEED NEEDLE
ADJUSTING VALVE
SCREW
THROTTLE
CABLE
ADJUSTING
SCREW
9ELLCRANK
FIGURE 33
2O