i am working with a straight 6 from a 1966 falcon that only stays running with the choke closed. i just had the carb rebiult and adjusted the timing also. my only guess is that it might be a vacuum leak. maybe in the intake manifold. has anyone else had this problem before?

 

even w/ vac leak most will run w/ idle mix screw turned CCW.

already tried that?

 

yeah i did try that. but thanks.

 

many methods for finding vac leak.

some spray starter fluid around suspect area and listen for rpm change.

be sure and check every vac line.

did you already do that?

 

busted diaphragms often cause vac leak in addition to affecting performance.

be sure and check auto trans vac modulator and distributor vac diaphragm.

did u already do that (where applicable)?

 

you mean someone did it for you? was it a complete carb rebuild using all brand new gaskets, jets, needles, etc from the kit, or was it just take apart and clean old parts routine? (nothing wrong with those sometimes, I'm just asking) was the intake manifold removed also? do you have the luxury to put on another carb on there to see if it's your carb and if it will run fine with a different one, sometimes that really helps, and is a time saver

what ever it is / was please post an update here so we know what you did to fix it when you do

 

manual choke or electric choke?
leave it closed until the car is warm. can you keep it running with your foot on the pedal?
maybe someone adjusted the idle with the choke being on and choke off the rpm drops til it dies??? could be as simple as that