I have a Motorcraft 4160 that is made by holley. It came with a hot air choke I bought an electric choke kit from Holley and installed it on the carb. If I set the choke on any of the index marks that the black round cap lines up with when the truck warms up it will not kick off of the fast idle cam completely. It will stay on the last setting on the fast idle cam I cam take my finger and push the fast idle cam down but as soon as I give it throttle it resests on the fast idle again. The only way I can get it to go down to a normal 650rpm idle is to turn the black choke cap clockwise about an inch past the index marks which makes it hard to start of a morning. Is there an adjustment that I can make to help this choke work better?
Check to make sure you have a good, constant 12v power to your choke. There is a flat plug on the main harness that runs across the rear of the engine bay that looks like it should have 2 contacts but doesn't. It should be roughly behind the carb on the choke side. It is the factory electric choke power source. Can post pic tomorrow if needed.
I thought the question was how to adjust the fast idle index, not how to power the choke. Fast idle index (e.g., how much of choke travel the fast idle stays engaged) is usually adjusted by a set screw, or bending linkage. Not sure on the 4BBL Motorcraft.
Make sure your hooked properly inside, it will move the choke plate both ways when turned opposite directions, then set it where you need it to be and it will be fine as long as everything moves freely with the throttle opened. I have had new carbs that didn't like those marks very well so I just set it to where the plate just stops closing and usually need to go a little more, but that is a good starting point, weak but it won't flood it out either. I think one in 3 maybe, are close to the marks when finished.