Carb Issues Poor idle after warm up?

[goodyear1984]

when it runs crappy did u look to see the choke position?so this was a brand new in box unit?does it only run crappy at an idel or driving it too?...i would run it and when it starts to act up look and see where the choke position is ,should be open if its warm...if it is opened look to see if the fuel is dripping out or if its got a nice flow..also what are ur cam specs and is ur timming set right...good luck man let us know how u make out

[trndkll67]

Sorry for the delayed response, been out of town....

The cam specs are:

Intake 448
Exhaust 472

Duration .050
204 Intake
214 Exhaust

I replaced the old 1406 with the Edelbrock 1400 600cfm. I got some flack from edelbrock becasue this carb is "prescribed" for a SB chevy, BUT its the exact same as a the 1406 except with no linkage adapter. I installed the linkage adapter and still have the same problems. Edelbrock says I can't tune it for the 302 except by trial-and-error. I thinks thats BS, but what do I know!

Its still running poor at warm idle, I have adjusted the high idle screw and haven't noticed much difference. I've got the choke set at "one notch forward". Should I toss it and a get a 1406, or go with something larger (>650cfm)?

[Elvis]

Well, I just put the same carb on my 302 and it runs great right out of the box. The automatic choke is 1 notch right of centre. I have my choke wire hooked up to the "I" pole on the solenoid. Perhaps you could check that or the ground. E.

[trndkll67]

Elvis:
Do you have a 1406 or a 1400? What rod size are you using? I'll try the choke wire trick; it's currently grounded to the back of the carb; what problems would that indicate if "your way" works? I guess a bad ground?

[Elvis]

Sorry, I misunderstood. Mine is a 1406. You should have a red and a black wire from the choke. The black should be grounded to the carb base and the red goes to the power source. As I stated, mine goes to the "I" pole on the solenoid. Good luck. E.

[trndkll67]

Elvis:

Ok, that's basically what I had before, except my ground wire went to the back of the carb. Red to the power.

I'm just concerned the rebuilt 1406 isn't getting the engine enough fuel. I figured the brand new 1400 (being the same size) out-of-the-box would be a better indicator of if that carb size is "big enough" but the result was no better. I'll give edelbrock a call and see what they reccommend...

Thanks...

[Gearhead999]

The size of the carbs you're talking about aren't going to change the idle of the engine.

Have you checked for a vacumn leak?? Maybe pwr. brake booster, vac. advance, etc. Or maybe the intake manifold gaskets are leaking.

What type of vacumn do you pull at idle?? Where is the timing?? The float level will also effect the hot idle. This type stuff effects the idle quality also.