[Gaz64]

My 2 cents:

I would get a fuel sample from the tank and analyse ethanol/water percentages.

Replace all flex hoses with alcohol (ethanol) compatible hose.

Flush lines after assembly from rear to front prior to fitment the carburettor.

Strip and rebuild carb as necessary. Blow all passages clear with air, ensure air bleeds are clear, ensure accelerator pumps operate correctly (no stuck outlet check valves etc).
Ensure float levels are correct. Throttle plate to transfer slot relationship is correct, all mixture screws at 1.5 turns out.