CONDITION

     PROBABLE CAUSE

     CORRECTION

Engine stalls when transmission is put into gear.

1) Incorrect choke pull-off adjustment.
2) Fast idle RPM incorrect (too slow)
3) Engine running too lean because of vacuum leak or dirty jet.

1) Readjust the pull-off or replace if necessary.
2) Speed up the fast idle to factory specs.
3) Check for vacuum leak. Flow test carb to check jetting.

Hesitation, stalling, stumbling, flatspot, or deadspot during acceleration: Backfiring or spitback up through carb.

1) Vacuum leak.
2) Ignition timing retarded too far.
3) Accelerator pump nozzle has dirt in it.
4) Accelerator pump cup swollen up from contact with bad gas or chemicals.
5) Economizer jet too small or partly blocked.
6) Choke pull-off open too far.
7) Secondary throttle plates not closing all the way.
8) Vacuum hoses hooked up wrong.
9) Idle jet partly blocked with dirt.
10) Distributor timing not advancing properly. (worn breaker plate, worn shaft, pin hole in diaphram, crack in hose, etc.)

1) Check for vacuum leak & fix it.
2) Reset timing.
3) Clean out the nozzle tip.
4) Replace the pump cup.
5) Clean out economizer jet & check the size.
6) Adjust the pull-off tighter.
7) Fix it.
8) Connect up right. Be especially careful of the EGR & Dist. connections: sometimes the pipe locations are reversed on Rochesters.
9) Clean out the jet & any other dirt that is in there.
10) Check distributor and all related systems carefully. Replace defective parts.

Hesitation, deadspot or stalling after first mile of warmup.

1) Defective electric assist on choke
2) Defective accelerator pump (low output).
3) Float level setting very low.
4) Bad ignition condenser.

1) Replace it.
2) Replace it.
3) Adjust to factory specs.
4) Replace it.

Periodic backfiring with black exhaust smoke: Deadspot, flatspot, hesitation, stumbling, backfiring.

1) Plugged heat crossover system in manifold.
2) Defective source of hot air up to the carburetor.

1) Inspect and clean passages in intake manifold and heads. Test heat riser valve, replace if defective.
2) Check and replace as necessary: heat shroud duct, temperature sensor, vacuum door motor, manifold vacuum supply.