Engine continuously stalls until hot.

[BPOE1975]

455, 4x-8, Comp XE274, HEI, factory intake, quadrajet w/electric choke.  Re-adjusted valves, leak down test on all cylinders, compression checked.  When cold, engine will fire and run a few second then stall.  Does this continuously until it is hot then it runs fine.  Even if I hold throttle at 2000 rpm is will start stumbling and stall.  Choke flaps close when I tap the throttle.  Adjusted choke pull off to 3/16 inch.  Adjusted coil to be rich and comes off when thermostat opens. When it fires the flap goes way beyond where I set the pull off.  This engine vacuum pulling flaps open? If I have that much vacuum I would think I have enough to pull fuel off the bottom of the runners?  My factory car mechanic swears it is the cam but everyone else thinks it is the carb.  CVMS specified the parts and built it turn key and in all of my research this cam should only be considered radical by any means which means I should be able to get it to run?  What is going on?  Please, please help!!!  I don't want to dig into the engine for a cam change.     

[73 Z28]

Has the carb been rebuilt? If so, give some info about jet size, idle mixture screw setting ,etc.
Starting and stalling seems to point to not enough fuel being delivered to a cold engine.

[Cliff Ruggles]

What is the carburetor number, and what has been done to it for your application?.....Cliff

[BPOE1975]

17057502 - 17054779.  77 Chevy.  Was "custom built" for my cars specs by SMI.  Had it built yeas ago, before I knew about Cliff's High Performance.  I have no indication of what size anything that was done or how it was set up.  It fires up immediately then pulls off way past where I set the choke pull off. It does seem to run better if I hold down the choke flap to where the choke pull off is set.  Can't figure out how to get the flap to hold down?  I turn the choke housing really rich but whatever is causing the flaps to open so far is over powering the coil?  Ready to pull it off and send it to Cliff.  What is the turn around time?

[73 Z28]

Tipping in the choke and improving the idle quality indicates it is too lean at cold startup. Try backing out the idle mixture screws 1 full turn , then perform another cold start and see if this cures the problem, if not call cliff as it will prolly need to be gone through. You also indicated that you bought this carb years ago, was it used and then been sitting awhile? That may have resulted in some restricted passageways in the carb leaning it out.

Good Luck!!

[Cliff Ruggles]

1977 California carburetor.  Pretty lean carburetors for what you are doing.  Sounds like it wants more fuel just about everywhere.  Any idea how it is set-up?.....Cliff

[Schurkey]

When cold, engine will fire and run a few second then stall.  Does this continuously until it is hot then it runs fine.  Even if I hold throttle at 2000 rpm is will start stumbling and stall.  Choke flaps close when I tap the throttle.  Adjusted choke pull off to 3/16 inch.  Adjusted coil to be rich and comes off when thermostat opens. When it fires the flap goes way beyond where I set the pull off.  This engine vacuum pulling flaps open?

What's the fast idle speed?

I would expect the choke coil would have released the choke LONG before the thermostat opens.

3/16 seems "rich"; but it could be correct for your carb.

Any chance the engine is dying from too much fuel instead of too little?