It might be running rich. Get a can of carb. cleaner and spray everything in and out and with the engine running, including the linkage. That might help and is easy to do. If not you'll need a shop to adjust it for you. The auto choke housing is located on the left side of the carb. as you are looking at it from the front. You'll see a black housing with three screws. On the housing you'll see index marks with lean and rich on it. Check to see where the notch is aligned. To adjust it all you will have to do is loosen the screws, don't remove them, and slightly turn the housing to where the notch indicates one line to the rich side. Re-tighten the screws and you're done. If you would rather not touch it have a shop set it up for you. Cleaning the carb. in and out might save you a trip. I don't think the springs are causing the problem. Don't forget there should be a solenoid at the front right side of the carb. that is there to keep you from stalling out on a hard stop and it will bump up the idle if you have a/c. That can be adjusted also.