satisfactory idle mixture setting. Repeat this pro
cedure with the other needle. If this adjustment
results in an increased idle rpm, reset the idle
speed screw to obtain the specified idle rpm, and
again adjust both idle adjusting needles.
B. Adjusting the Automatic Choke
1. The automatic choke is accurately set at
the factory to give the best possible all weather
operation. To return the choke to the original
setting, line up the index mark on the rim of the
thermostat cover with the large center indicator
on the choke housing.
2. If for some reason a richer or leaner mix
ture during the warm-up period is desired, it can
be obtained by rotating the thermostat cover.
Never set the index mark on the cover more than
two graduations off the large center indicator on
C. Adjusting the Dashpot
1. Start the engine and allow it to reach
normal operating temperature with the automatic
transmission drive selector in neutral.
2. Turn the dashpot adjusting screw down
until it no longer fully compresses the dashpot
stem when the engine is idling at its normal oper
ating temperature. If the dashpot adjusting screw
is set too high, it will compress the stem fully and
stop the throttle lever before reaching the idle
position. This will result in a high idle speed and
make it impossible to reach a lower idle speed
adjustment with the idle speed screw.
3. Set the idle speed and mixture according
to preceding instructions, being certain the idle
speed screw is on the low step of the fast idle cam.
4. The dashpot adjusting screw should then be
set so that the specified clearance exists between
the adjusting screw and the dashpot stem when the
stem is fully compressed. The proper clearance
for the Mercury dashpot equipped carburetors can
be found in the current Holley Carburetor Specifi
cations Catalog, Section IV, Division C.