I don't understand the problem???

With auto choke carbs, the engine should be started by pushing the footfeed to the floor and RELEASING. This should set the fast idle, the return springs have nothing to do with the operation of the fast idle.

You might have to pump the footfeed a couple of times, but once this is done, REMOVE foot from footfeed.

Jon

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop