Could it be a carb Problem?

The big thing is to clean out the float bowls. When the gas in there evaporates, the solids harden to an evil semi-solid sludge that settles in the lowest crevices, namely the fuel wells. (Nothing you can mix into the gas in the tank will get that out) You need the product that is specifically formulated to dissolve it and full strength. The new environmentally friendly stuff they sell over-the-counter now, is so wussy, that this can take a day or longer. You can thank the tree-huggers for that.
The good stuff is still available but it costs a small fortune. For a one-time use it's probably cheaper to send your carb out.
The stuff in your tank will not dissolve back into the fuel. And it will not likely migrate out of there. But it tends to separate from the insides of the tank and slosh around as a slimey sheet, and may cover the pick-up sock leaving you stranded. If at one time ALL of the fuel in the tank evaporated, then a good percentage of the sock may already be plugged. So it's in your best interest to at least look into the tank.
Any fresh fuel you put in there will sit on top of the sludge/varnish, and if it makes it thru the sock, then you will never know the gunk is in there...... until one day it plugs the sock, and then yur walking. It can happen that if you shut the car off, the sludge moves away from the sock, and then the pump can suck gas again, leaving you baffled.... until it happens again. Ask me how I know. I eventually bought a new tank.