Idle Speed And Carburetor Adjustment; Volts - Preliminary Checks - Sears 161.216500 Owner's Manual

IDLE SPEED AND
CARBURETOR ADJUSTMENT
1. The engine should be at normal operating
temperature for this test. Many cars built in
1970 and later have idle mixture screw limiter
caps that restrict adjustment. On these cars the
carburetor should be adjusted according to the
procedure in the manufacturer's service manual.
2. Shut the engine off and conned the test leads
as shown in FIGURE 1 or for Bectronic Ignition
Systems and late
model
COI"5,
see
FIGURES
1,2,
3, 4, 5, 6, and 7. Set the fUNCTION SElfCTOR
Knob to the RPM position.
3. Consult the manufacturer's service manuaHor
the location of the idle speed adjusting screw
and the idle mixture adjusting screw (or screws).
Make idle speed and mixture adjustments.
according to the procedure outlined in the ser-
vice manual or as specified on the decal in the
engine compartment.
Figure 19 illustrates typical locations of the idle
speed and idle mixture screws on single and
multi-barrel carburetors.
TYPICAL IDLE SPEED AND
MIXTURE SCREW LOCATIONS
FIGURE 19
SINGLE BARREL CARBURETOR
DOUBLE BARREL CARBURETOR
4. Start the engine and turn the idle speed screw
until specified idle speed is indicated.
5.
On engines without exhaust emission control sys-
tems, turn the idle mixture screw in (lean) until
the idle speed starts to decrease, then turn it
bock out (rich) just until the idle speed reaches a
maximum. Further richening past this point will
only waste fuel. This should be' done slowly to
allow engine speed to stabilize.
6. On multi-barrel
carburetors, repeat this proce-
dure on each idle mixture screw until the highest
idle speed and smoothesf operation is obtained.
If the engine idle speed is now higher than the
manufacturer's specification, turn the idle speed
adjustment screw until the specified idle speed is
indicated and readjust the mixture screws with
the above procedure. .
7. NOTE: On engines equipped with exhaust emis-
sion control systems, air injection pumps and pos-
itive crankcase ventilation, refer to the decal in
the engine comportment or the owners manual
for idle adjustment sp_ecifications.
o
\'_PLUG END
OF
VACUUM LINE
DISTRIBUTOR VACUUM HOSE CONNECTION
FIGURE 20
VOL TS-PRELIMINARY CHECKS
The VOLTS switch position is used to test the crank-
ing and charging volts in the vehicle.
CONSULT THE OPERATING MANUAL OF THE
JI' •.
VEHICLE BEING TESTED FOR SPECIFIC VOLT-
AGES AND TEST PROCEDURES:
The following information will serve as a general
guide for making charging system tests.
Before making VOLTS tests:
Check the fan belt - it should be tensioned
according to the manufacturer's-specifications.
9