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Idle too lean, rich off idle 3310 style 750 vacuum secondary.

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  • Idle too lean, rich off idle 3310 style 750 vacuum secondary.

    If this has been asked already I'm sorry. I've tried MANY times using search and all I get are results from EFI forums.
    I have a 750 vacuum secondary, 70 primary jets, 351 Cleveland, 244/244 @ .50" cam, single-plane intake. This results in very low vacuum at idle, 4-5 inches vacuum at 800-1000 RPM in park.
    I have holes drilled in my throttle blades and I opened secondary set screw to get it to idle with the transfer slot square shaped. AFR gauge shows 15:1 at idle, and just off idle driving slow it reads 10:1. It reads 10-11:1 cruising at 40 MPH. Too rich for my liking. At WOT it runs about 12.8:1 and pulls good, but the secondaries take to much time to open. That could be another thread. Let's talk about lean idle, rich off idle first.
    I have the idle mixtures screws at 4 turns out (they are ready to fall out). I haven't measured the idle feed restrictor size in my metering block yet. My plan was to go up 0.001" at a time and try to enrich up my idle to about 13:1. If I do that, will that also enrich up my off idle rich condition?
    What are your thoughts? Thanks, Danford1