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Old 07-25-2012, 06:44 PM
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idle mixture question

I was hoping one or two of you would be nice enough to let me bounce some logic off you and let me know if what I'm thinking makes sense... or if I'm way off.

SBC, dual quads, Edelbrock RPM Air Gap dual plane intake.

Just had the engine rebuilt and after about 125 miles pulled the plugs. #1 was carbon fouled and fuel actually dripped out of the plug hole. The other 7 were fine, though #3 was slightly carbon fouled.

The last time I drove it, I idled for probably 3 minutes with no throttle before shutting off (lining up back and forth when backing into garage).

The left-side idle mixture screw of the front carb was turned out about 1/2 to 3/4 more than the right side. It would be this idle mixture screw that would control the left-side venturi's and thus putting more fuel into cylinders #1 and #3 at idle. Since there was actually fuel pooled in the #1 cylinder and the last time it ran I'd idled it without throttle for 3 minutes or so before shutting it off, I'm thinking it's just an idle mixture issue and by turning the left-side screw in more (which I've already done), that should take care of it. Does this make sense or is it likely to be more complex and involve jetting, metering and/or float?

I'll know more after the next time I can take it out, but I hoped to get some feedback on whether my thinking was sound.


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Old 07-25-2012, 07:40 PM
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I have a pressure regulator set to 4.75 psi.

Lunati cam: .477 lift, 275 adv dur, 225 dur @ .050.
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