1965 starting issues

[Rat_Basterd]

Sorry ahead of time for the walk of text

So my truck would start fine until it ran out of gas I left it sitting for a while then finally got around to putting gas in it to get it goin again. Here’s where the issues started. Turned to crank. Nothing. Figured I had a dead battery so I take it to get it charged. Bring it back fully charged and good to go same thing. I check some wires I don’t touch much just look around then start again same thing I sit thinking what can be wrong for a bit and just try again because I’m sitting in the driver seat and it starts cranking but I have no gas in the carb so it’s not fully turning over. I put some gas in the carb go to crank again and nothing. I’m getting extremely frustrated because I basically did nothing and results changed. I start troubleshooting I go through all my wires and everything is connected properly then finally I’m able to test the voltage to my starter solenoid. Wire straight from the battery is reading 12.4 volts. Wire going to my ignition switch when it’s cranked is only giving me 3.8 volts. Check the voltage at the harness connector to the firewall. 4 volts. I go checking the wiring from the firewall to ignition and everything looks normal. I get a jumper wire and connect the the 12.4 to the ignition part of the solenoid and I get a spark and a crank do it again same thing. Hop in the truck turn the key it starts cranking. Add starter fluid to carb. Turn the key nothing again. Use the jumper it cranks then I hop in the truck turn the key and it fires right up. I drive around the block a few times to get parts moving and all that. Park the truck. When I turn the key off it sputters out for a while instead of shutting off right away. Sit a minute turn the key again, nothing. Can someone give me some advice please. I’m getting extremely frustrated.