Throttle return is a very important aspect of carburation. You want your carb to open all the way on acceleration, buy you also want it to close properly when you lift your foot off the gas pedal.
Here is a short guide on how to install a throttle spring bracket the right way.
Some personal background (if you’re in a hurry, feel free to skip this and get straight to the guide):
I recently replaced my leaky Autolite 2100 carb on my ’65 mustang with a 2-barrel Holley 500cfm street avenger. The switch went well, but i notoced my curb idle RPM woudn’t go below 1500, which is way too high. The car would also drive 30mph without even touching the gas pedal, and stopping at a red light required alot more pressure on the brakes. The old, worn-out return spring which came with the Autolite 2100 was way too weak to pull the mighty Street Avenger back into the fold.
Holley throttle return spring bracket kit installation
To be continued… very soon!
Here’s an image of all the separate parts that come with your holley return spring replacement: