If you are having fuel separation in the carbs, then you may also have it in the tank
May require pulling the tank and flushing it out to get any residual crap from the bad gas and the petcock flushed. Hopefully the brown gunk isn't the rubber in the hoses being attacked by the fuel. Ethanol fuel wasn't hose friendly, requiring a change to the fuel hoses to make it compatible.
You may need to tank the carbs to flush the passages. But, a clean of the tank and petcock should get you close to running. Test theory with an auxiliary bottle of gas serving as the tank before you clean it.
If the problem clears, you know that the tank is contributing. Of not, then you need to clean the carbs or ultrasonic bath them to clean the carbs.
Good luck,
David