Club 80-90 Forums

HI everyone, I’ve gathered some really useful advice from the forum over the last few years, and hope you may be able help with an issue I’m having.
We have a 1981 t25 microbus 2.0 air cooled, twin carbs. For the last 12 months it has started fine, but after about 3 minutes it will stall. It then struggles to start for a while, but will then run fine. I’ve replaced the coil, leads, rotor arm, plugs, module, and can’t find any air leaks. There is a slight smell of fuel. 
Any help would be appreciated?
Could it be a choke issue?
Thanks, Jim

I'd strip the carbs down and clean them internally including all the jets.  Also change the fuel filter underneath and close to the fuel tank.  Check the rubber/flexible fuel lines.......

Check the chokes are operating properly and that the carb linkages are balanced