On a 1930’s Ford, the Stromberg 97 can rely on a spring in the the firewall pedal linkage to snap it back to idle when you lift your foot off the gas. Yes, the accelerator pump spring does provide some spring-back, but you shouldn’t rely on it as your sole return spring.
So if you are using a single 97 in a different application, for example, on a Model A Ford. Or without a sprung pedal linkage, you still need reliable return spring. Just slide this onto your throttle shaft. Rest the end on the base casting. Twist to adjust the tension and tighten the set screw.
