[TransAm 474]

Ok, this is gonna be lengthy, but I want to explain everything we did today. I think we have the carb getting a LOT closer now .... in the end, it was just mostly "user error" on our part �� .... I told you all that the Mixture Screws didn't have any response because of what I thought was the Primary Blades being cranked too far open. We were gonna take the carb back off and increase the Idle Bypass Air, because I thought that is what it was wanting. It turns out, that they weren't too far open at all. First thing I noticed today, was when I checked the ported vacuum source, it didn't have vacuum on it at Idle like I was expecting, so I grabbed a light and looked down the primary bores, no Nozzle Drip at all. The error was, a few days ago, when I was adjusting the Mixture Screws from their baseline setting of 5 Turns out, I didn't try adjusting them IN anymore than maybe 1 1/2 turns from that baseline setting(3 1/2 turns from seated), so it wasn't responding, same with adjusting them OUT, there was no response. Today, after I verified the blades were not cranked open, and had no Nozzle Drip, I decided to crank the Mixture Screws IN to try and seat them with it idling to see what happened, low and behold, they started responding, so it just wanted less Idle Fuel at the Screws than I was expecting. Anyway, we ended up with them at 2 3/4 to 3 Turns out from Seated for best Idle and Vacuum. Initial Advance is set at 12°. I did however still do the test pulling the small vacuum hose off the choke pull off to see what happened, and the Idle RPM still increases 75-100 RPM, so it might still be indicating that it could use a little more Idle Bypass Air. Idle Vacuum at 780-800 RPM is right at 10 to 10.5", so it seems maybe a bit low still, but I am not sure what we can do to increase it. We did try the Vacuum Advance hooked to Manifold vacuum as well, and it increased Idle RPM as well, so I lowered the curb idle screw back to 780-800 RPM, and it did seem to increase Idle Vacuum a little maybe, but not a huge amount, maybe .5" to 1" at best. We also did the APT Adjustment with the Tip-In Procedure in Cliffs book up at 2000 RPM. Baseline setting was 3 1/2 Turns up from seated, and I found that it actually lost a little RPM when tipping in the choke flap, so we adjusted back IN until RPM now increases 50 to 70 RPM when the choke Flap in tipped in, which ended up at only 1 1/4 Turns up from seated. Throttle Response from a stand still definitley Improved after adjusting the APT. It is Idling pretty well, and stays running nice when placed into gear now. I might still be able to make improvements somehow. I wish it had a little closer to 11.5 to 12" of Vacuum at Idle, but it may be as good as it gets. Anyway, I thought I would check in and update you all.