S&S Cycle Super E and G Series Shorty Performance Carburetors for 1936-84 Harley-Davidson Big Twins and 1957-85 Ironhead Sportster Models - Manual (Page 11)

11
Picture
20
1- Start engine and run until slightly warm
(approximately 1 to 2 minutes).
2- Turn RPM adjustment screw to obtain idle of
approximately 1000 RPM.
3- Turn idle mixture screw clockwise, slowly leaning
mixture until engine starts to stumble. Next, turn
screw counterclockwise, slowly richening mixture,
until engine RPM rises and then falls off. Mixture
adjustment is correct when screw is positioned about
halfway between these points, or generally 1⁄4 to 1⁄2
turn out from lean side of adjustment range.
NOTE: Turning screw out (counterclockwise) makes idle mixture
richer. Turning screw in (clockwise) makes mixture leaner. Normally,
correctly adjusted screw will be between 11⁄4 and 3⁄4 turns out from
bottom if intermediate jet size is correct. Note that mixture screw
must be adjusted according to Step 3 above. Do not leave screw at
initial 11⁄2 turn setting without fine tuning.
4- After initial idle mixture adjustment, reset engine idle
to approximately 1000 RPM. Lower idle speed can
cause hard starting, poor throttle response, erratic
idle and unnecessary engine wear.
5- After engine has reached normal operating
temperature, repeat Steps 3 and 4.
IDLE CIRCUIT NOTES:
• If idle adjustments are made before engine is fully warmed,
idle mixture will be rich when engine reaches operating
temperature. If ambient temperature is below 60 degrees,
engine may require 10-15 minutes of normal riding to
reach operating temperature.
• Whenever intermediate jet change is made, idle mixture
screw must be readjusted.
• If the idle mixture screw is more than 13⁄4 turns out after
idle mixture is correctly adjusted, it is a fairly good
indication that the intermediate jet may be too small and
should be changed to the next larger size. If the idle mixture
screw ends up less than 11⁄4 turn out, the intermediate jet
may need to be changed to the next smaller size. Be aware
that idle mixture screw adjustment can be effected by other
factors, but can quite often indicate rich or lean
intermediate jetting.
• If idle mixture screw is turned completely in, engine should
not run at idle. If engine continues to run at idle with idle
mixture screw seated, recheck initial setting of idle speed
screw, and make sure enrichment plunger is seated. This
may also indicate damage to the idle mixture screw needle
and/or its seat.
B- Troubleshooting Tips - engine will not idle:
1- Improper idle mixture or rpm setting.
2- Intake manifold air leak.
3- Incorrect ignition timing, malfunctioning automatic
advance mechanism, or other ignition problem.
4- Foreign material in air or gas passageway in carb
causing gas flow restriction to idle or intermediate
circuit. Picture 21 shows intermediate air bleed
metering hole. Clear holes with compressed air.
Picture
21
Do not use wire or drill to clear hole. If size of hole is altered,
starting system will be altered and carburetor bowl
irreversibly damaged.
Compressed air and particles dislodged by compressed air are
potentially harmful to eyes and body. Wear protective
goggles when using compressed air and always direct air
stream away from yourself and others nearby.
5- Enrichment/fast idle plunger not seated causing
excessively rich mixture. Be sure enrichment lever is
fully disengaged (in down position) allowing plunger
to bottom and seal passageway. Remove air cleaner
backplate. Lift and release plunger several times,
letting it "snap" closed to fully seat against carb body.
When backplate is reinstalled on carb, be sure lever is
engaged in plunger properly and that plunger is not
lifted as mounting screws are tightened. See Picture
17 on Page x.
6- 1⁄4" insulator block between carb and manifold
omitted. Heat transfer from manifold to carb may
cause temporary rich condition at idle and low rpm
when engine restarted after being shut off for a short
time. Install insulator block to minimize heat transfer.
C- Adjusting Intermediate System - (See Jetting Chart Page
XX) Intermediate rpm range is used most often under