Carb, AC, and Wiring

[Nedwinters]

Got a few questions:
1. I have a bare wire right where all the main wires plug into the fire wall under the dash, just above the fuse box. Can I just pull the wire or is that all one plug? See photo:

2. After along drive, it takes about 20 mins to get the truck started back after I have let it sit for about 15 mins. I believe if I replace the carb, it will cure my problem. I have an original carb and want to keep everything pretty much the same, which carb would you suggest? See photo:

3. I am about to recharge my ac. Can I just recharge it with R134a? See photo:

Thanks.