To Adjust Carburetor; Preliminary Setting; Acceleration Test; Final Setting - Craftsman 917.258492 Owner's Manual

SERVICE ADJUSTMENTS
TO ADJUST CARBURETOR
(See Fig. 34 & 35)
The carburetor has been preset at the factory and adjust-
ment shouldnot benecessary, However minoradjustment
may be required to compensate for differences in fuel,
temperature, altitude or load If the carburetor does need
adjustment, proceed as follows:
In general turning the mixture screw in (clockwise) de-
creases the supply offuel to the engine giving a leaner fuel/
air mixture, Turning the mixture screw out (counterclock-
wise) increases the supply of fuel to the engine giving a
richer fuel/air mixture
IMPORTANT: DAMAGE TO THE NEEDLES AND THE
SEATS IN CARBURETOR MAY RESULT IF SCREW IS
TURNED IN TOO TIGHT
PRELIMINARY SETTING
• Be sure you have a clean air filter, and the throttle
control cable and choke are adjusted properly (see
above).
° With engine off turn idle mixture screw in (clockwise)
closing it finger tight and then turn out (counterclock-
wise) 1-1/4 to 1-1/2 turns.
FINAL SETTING -
o Start engine and allow to warm forfive minutes. Make
final ad ustments with engine running and shift! motion
contro ever in "NEUTRAL" position_
- With throttle control lever in "SLOW" position, hold
throttle lever against idle speed screw and adjust idle
speed screw to obtain 1200 to 1400 RPM
= While still holding throttle lever against idle speed
screw, turn idle mixture screw in (clockwise) until
engine begins to die and then turn out (counterclock-
wise) until engine runs rough Turn screw to a point
midway between those two positions,
• Continueto holdthrottle leveragainst idle speed screw
and adjust idle speed screw to obtain 900 to 1200 RPM.
Release throttle lever_
ACCELERATION TEST -
• Move throttle control lever from "SLOW" to "FAST"
position. If engine hesitates or dies. turn idle mixture
screw out (counterclockwise) 1/8 turn. Repeat test
and continue to adjust, if necessary, until engine accel-
erates smoothly_
High speed stop isfactory adjusted, Do not adjust- damage
may resulL
IMPORTANT: NEVER TAMPER WITH THE ENGINE
GOVERNOR, WHICH IS FACTORY SET FOR PROPER
ENGINE SPEED. OVERSPEEDING THE ENGINE ABOVE
THE FACTORY HIGH SPEED SETTING CAN BE
DANGEROUS. IF YOU THINK THE ENGINE-GOVERNED
HIGH SPEED NEEDS ADJUSTING, CONTACT YOUR
NEAREST AUTHORIZED SERVICE CENTER, WHICH HAS
PROPER EQUIPMENT AND EXPERIENCE TO MAKE ANY
NECESSARY ADJUSTMENTS.
IDLESPEED
SCREW
MIXTURE
SCREW
THROTTLE
LEVER
FIG. 34
THROTTLe= \ IDLEMIXTURE
LEVER SCREW
FIG. 35
23