Carter BBD confusion

1974 was the first year Federal regulations required a redundant double throttle return spring setup so that one spring could fail and the throttle would still close. That's why '74 and later carbs have a built-in throttle return spring but the '74-up cars still have the separate bracket-style throttle return spring. The most common way of retrofitting this easy, common-sense safety feature to an earlier car is to fetch a large-diameter regular pull-style coil spring with hook ends, just like the original throttle spring but larger in diameter. Place the original small-diameter spring (or its new replacement) inside the large-diameter spring. Hook both springs to the bracket and to the throttle lever. Voila…dual redundant throttle springs.

And no, you cannot remove the accelerator pump plunger spring and expect the carburetor to work correctly. It won't.