Carb Trouble

So today we put a holley 4160 vacuum secondary carb that i just rebuilt on my car. and it started right up, but it will only fun for a few seconds before it dies. it will only idle at around 2000 rpm. What is wrong?!?!?

i need your guys' help big time.

 

Need more info and time than I have this morning

 

ok so we got it to stay running but it wont idle below 1500 rpm without dieing. we cant figure it out. im thinking it might possible be a blocked passage... any way to ID this problem for sure?

 

what engine, and manual or automatic transmission?

First thought though, check for vacuum leaks.

 

Might be the timing is retarded too much. Set the timing first to 12* BTC, then close the carb's throttle all the way, then just crack it open. Then screw the idle mixture screws all the way in, then back out 1-1/2 turns each. Then start it back up. If everything's kosher, it should idle on it's own if the engine is warmed up. If not, tighten the idle speed screw down some more and play with the mixture screws, back each out til you get the smoothest idle. If you open the throttle blades too far, you'll uncover the idle transfer slot in the throttle bores, at this point, the engine will not respond to the idle mixture screw adjustments.

 

hopefully i will get to try those things today. timing is definitely part of the problem (backfires through carb). im gonna check with a local dude today see if he can see anything visibly wrong with it (ie. if i messed up the rebuild). we played with the tuning for hours. the blades might be it though, there is some space in between the throttle plate and the blades. i mess with that today for sure

 

302 c4. holley 4160 vac sec. list 6919.

checked all the vacuum lines, but it still seems like there is one.

 

You can try holding the choke partially(mostly) shut to see if that helps, if so it's a carb or vac problem vs timing issue...

 

we played around with that, when it is wide open it will stay running. when it is slightly open, the idle will drop; but it will also die. i dropped it off with a local dude that works out of his garage. he comes recommended from a nearby auto parts store.

 

problem solved. the dude said he couldnt find anything wrong with the carb; but when we put it back on, it fired right up and idles normally now. man it is awesome. im guessing when he went through it he might have cleared a blocked passage or something like that.