WOT carb cutting out.

[DusterDrew]

here’s a video. Happens under load at wot. Seems like it’s not getting enough fuel. Starts to cut of and lose power and backfire. If I step off the gas and reapply it goes away. I’ve been through the whole carb. Cleaned it up. New jets, metering rods, step up springs. Replaced fuel pump, checked all the lines they look good. Don’t know what’s causing it to do this. Any help would be greatly appreciated. It’s an Edelbrock 600 com carb on a mild 318.

 

[67Dart273]

Can't get it to play. Could also be bad coil or other ignition problem, or a valve/ cam problem. "Flat cam" an cause popping back through carb, as in flat exhaust lobe. This would be rhythmic one cylinder

 

[Dana67Dart]

Where is your dwell set (if you have points)

 

[AJ/FormS]

If I step off the gas and reapply it goes away.

It’s an Edelbrock 600 com carb on a mild 318.

#1Tighten up the secondary Air-door
#2 back your power-timing up to 34*@no earlier that 3200
#3 set your accelerator pump arm per instructions
#4, make sure the accelerator pump check weight is in it's receptacle.
#5 make sure the pump is spraying nicely, and continuously.
#6 Make sure the bowl-vent is open!

What cylinder pressure are you running?
What stall
What gears
Headers and duals? yes/no

The lower the stall, and the shorter the gears
the later you will have to stage the secondaries.

A mild cam, a low cylinder pressure, a 1700stall, 2.76s, and log-manifolds, with too early opening secondaries;
is an impossible combo.

 

[DusterDrew]

Thanks for all your replies. I really appreciate it. It does have dougs headers and it’s a 3 speed on the floor. Unfortunately it still has a 7 1/4 rear end in it but I do have a 8 3/4 laying around that I’m going to throw in this winter. I’m in the army and headed out to the field for a week but when I get back I’m going to look at the timing, cylinder pressure and run through the carb again. Unfortunately the guy I bought the car from had no idea what cam was put in there. Besides the cam, intake manifold and headers everything else appears to be stock.

 

[Cudafever]

How long have you had this car and has it done it from the beginning.
If not when did it start acting up.

 

[Rmoore]

Plugs, wires, cap, rotor

 

[DrCharles]

Plugs, wires, cap, rotor

Didn't Smokey Yunick say that 90% of carb problems are in the ignition?

I didn't see where you put a gauge on the fuel line to check the actual pressure during this misbehavior?

 

[67Dart273]

Didn't Smokey Yunick say that 90% of carb problems are in the ignition?

I didn't see where you put a gauge on the fuel line to check the actual pressure during this misbehavior?

^^This, and once you are "into" it, the accelerator pump has nothing to do with anything.