I have a '73 440 with a holley 4bbl that ran pretty good until recently. If I start the engine cold it will start right up and idle for about 30 seconds and then die. If I try to start it afterwards, it won't start unless I pump the gas a few times (I normally don't have to pump the gas at all to get it started so this is new). When it does start it just putters and dies again seconds later. The fuel pump is pumping fuel fine. I checked for obstructions in the fuel line. The I put a new fuel filter on hoping it would help, but it didn't. So the filter is clean. The carburetor is squirting fuel. I haven't touched the mixture screws because it was tuned fine the other day. Any thoughts? Thank you.

I timed the engine and adjusted the mixture screws several months ago and it has run fine until this started happening the other day. I haven't hooked up a vacuum gauge to it yet. I will give the carb cleaner a try.

You might go slightly richer on the mixture screws.

Pull the air cleaner and start the car while looking down the carburetor. Operate the throttle to keep it running if necessary. Look for proper atomization of the accelerator pump shot. If you can plumb in a fuel pressure guage, do it. You need a minimum of 4-5 lbs of pressure with a max of around 8. Any wild swings of the guage could mean that the fuel pump pushrod is wearing out, not giving a full stroke to the pump. The line may fill with gas but the pressure will be below acceptable levels. NEW fuel pushrods are available from Mancini Racing.

check for spark....if you have good spark, check the floats and/or needle and seats. You may have a float that is full of fuel and sank, or a needle/seat that is stuck open or partway open.

possible fuel pump or pushrod issue???? Disconnect the line at the carb, Disconnect the coil, put it into a container, Crank the motor a bit and check for adequate fuel delivery,

Will it run with the throttle further open? If so you have narrowed the problem to the idle circuit.
Then clean the gunk out of the idle circuit.

water in your gas???