Holley 1949 Non-Feedback
***UPDATED BY TSB #83-24-14
AUTOMATIC CHOKE FUNCTIONAL TEST
Choke Circuit Test
1. Disconnect the choke lead and connect the test light in series with the choke lead wire and ground. If light glows while engine is running, continue to Cap Continuity Test.
2. If light doesn't glow, perform the following:
Alternator Stator Center Tap
a. Light Doesn't glow: Bypass the stator lead wire and connect the light in series with the sator terminal and ground. If light glows, service stator lead wire or replace. If light doesn't glow, service alternator.
b. Stop engine. Remove test light and reinstall stator lead wire. Repeat choke circuit test.
c. Stop engine. Remove test light. Reinstall choke lead wire.
Cap Continuity Test
1. With engine Off and air cleaner removed, connect one lead of the test light to choke cap terminal, then touch the other lead to the positive post of batter. There is continuity if light glows. Remove light and leads.
2. If test light doesn't glow, connect a jumper lead between the choke cap ground strap and the carburetor body. If the light glows, service contact between carburetor body and choke cap ground strap. Repeat above step.
3. If the test light doesn't glow, replace the choke cap, then repeat Step 1.
Choke Time-To-Rotate Test
1. Set fast idle adjustment screw on the highest step of fast idle cam.
2. Following the choke tester manufacturer's instructions, cool choke housing externally except as follows:
a. Refer to choke come-off time specification. Turn off choke tester momentarily at 1 min. intervals until bimetal closes and seats the choke plate lightly in the air horn assembly.
3. Start the engine, and set fast idle adjustment screw on kickdown by depressing throttle one time. Measure choke plate rotation time. (i.e. From point of starting engine til choke plate is vertical). If choke come-off time does not meet specification, replace the choke cap, then repeat all three steps.
CARBURETOR CHOKE ADJUSTMENT
Choke Plate Pulldown
1. Following choke tester manufacturer's instructions, cool choke housing externally except as follows:
Turn-off choke tester momentarily at 1 min. intervals until bimetal closes and seats the choke plate lightly in the air horn assembly.
2. Activate the pulldown motor by applying an external vacuum source to free end of pulldown motor vacuum hose. Apply light pressure to the upstream edge of the choke plate in the closing direction to remove clearance between pulldown motor clevis and modulator stem.
3. Using a drill, measure the clearance between the upper edge of choke plate and the air horn wall. Be sure drill is held vertically, parallel to air horn wall.
4. If adjustments are required, perform the following procedure:
a. Remove carburetor from engine. Drill 1/16" diameter through the pulldown adjustment screw lead seal plug (only for original pulldown motors)
b. Use an easy-out tool and remove plug. Apply Black Silastic to end of adjustment screw boss. Before inserting allen wrench, apply external vacuum to pulldown motor. Repeat Steps 2 and 3. Adjust screw in or out as needed.
c. Check for vacuum leak after installing a new lead plug in adjusting screw access hole and stake while supporting the pulldown motor bracket.
d. Install pulldown motor hose on pulldown vacuum supply tube on carburetor body. Fast idle cam index check must be performed. Install carburetor on engine.
Fast Idle Cam Index Setting
1. Cool choke housing externally.
2. Position fast idle screw on high step of fast idle cam. Activate the pulldown motor by applying an external vacuum source. Apply light pressure to the upstream edge of the choke plate in the closing direction, to remove clearance between pulldown motor clevis and modulator stem.
3. Allow fast idle cam to drop by opening the throttle slightly. Close throttle and measure the clearance between top edge of fast idle rpm adjusting screw and shoulder of fast idle cam high step fast idle cam index. Dimension A should be .51 to .76mm.
4. Remove light closing pressure from upstream edge of choke plate. Open throttle to WOT position and return slowly. Fast idle adjustment screw must contact lower end of fast idle cam kickdown step by at least half of its diameter for carburetors with four step cams or must contact third step by at least half of its diameter without contacting second or fourth steps for carburetors with five step cams.
5. Fast idle cam index is within specification if steps 3 and 4 are ok.
6. Perform the following procedure if an adjustment is needed:
a. Repeat steps 1 thru 3, bending fast idle cam link at loop as required to obtain correct dimension. Repeat steps 3 and 4 again to verify setting.
De-Choke
1. Cool choke housing externally. Hold the throttle lever in the WOT position.
2. Use a drill to check clearance between the upper edge of the choke plate and the air horn wall. Carefully bend the tang on the throttle lever as needed to adjust.