I haven't used carb dip for probably 40 years. But leaving a zinc alloy body in overnight often would damage the castings beyond use! I hate to see even a Rochester B treated in this fashion.
30 minutes was sufficient. The new dip is probably not as stout.
Agree with Jerry 100 percent about the softening of deposits but not removing them.
When I was still doing carbs, I used an ultrasonic cleaner; with a very exotic cleaning agent.......................................Dawn dishwater soap.
Ultrasonic cleaners are much cheaper than when I bought mine ($5200. for a quality USA-made unit large enough to dunk a Holley 4150 complete), but even at current prices, the average enthusiast may not be able to justify the cost.
A "poor man's" cleaner can be made from an empty 3-pound metal Folger's coffee can. Simply mix up a good solution of Dawn and water, place with the carb parts in the can, and BOIL. The heat and the soap loosen the deposits, and the roiling action of the boil flakes the deposits off, and the grease will be absorbed by the Dawn.
Jon.
