Starter/Electric/Carb Problem 1985 GMC

[Harrycarry]

Hi All, This is a great site. I have a 1985 GMC 1 Ton with a 454 motor. When I turn the key nothing happens until I tap the starter which sparks around the solenoid then go back in the cab and it cranks. This also effects the headlights and other electrical items. Another unrelated problem is with the carb I believe. The other day the truck was running fine until suddenly it backfired thru the carb and barely ran at all unless I floored it but just barely ran. I changed the plugs, dist cap and rotor. No difference but when I tap around the carb it starts running pretty good then dies again. The carb is a Rochester Q-Jet which I don't believe is original because it's not electric choke. Any advice would be greatly appreciated. The truck has been sitting for a couple of years and I'm slowly getting back to working order.