Engine Sputters After Key Off

Hello, I just found the forum and would love some help here.

I don't have all the specs infront of me but in general I have a '68 Nova with a Crate 350, 4BL Edlebrock on Edlebrock intake. Just got it up and running, tuned carb to Edlbrock's Lean-Best idle specs and set timing to '68 Chevy 350 specs.

It lagged at start and at WOT and did this sputtering after I've turned it off. A friend suggested I was running rich, so I tightened the 2 idle mixture screws 1/4 turn twice (1/2 turn) to lean it out and the engine is much more responsive but will still sputter after I turn it off and if its sat for many hours, after start up, the first exceleration will almost kill the engine.

I'm sure there is a simple thing I'm missing here and would really appreciate someone pointing it out.

Thanx

If by sputtering you mean it runs on for a few rpms after ignition is turned off it means your primary throttle plate isn't closing all the way. Could be your return spring isn't pulling enough (set too short, not strong enough, whatever), or the linkage is binding, throttle plate is hanging up if gasket is wrong, or idle linkage screw set too high. Check everything that affects the linkage:wires, air cleaner, and so on.

Try advancing the timing. Retarded timing runs hot, causing hot spots that will keep the engine firing without spark. Set the idle speed lower if possible, after the engine is broken in, of course. Never idle a fresh engine slow.