If you have been using regular rubber, any petroleum based product will turn it to goo. When I was building my last rotary engine, the factory service manual from Mazda said to coat the housing seals with petroleum jelly and then install them in the grooves. So I did that, but I didn't torque the tension bolts down. I just assembled the engine and lwt it sit until the next day when I could get my torque wrench from the shop. 24 hrs later, the seals swelled out of the grooves and were melting down the side of the engine. There are special types of rubber that are petroleum resistant that get used when in the presence of fuel or oil. That's why I opt for the clear vinyl tube that I used for going from the tank to my carb, and likewise why I don't expect my ghetto heater hose manifold to last too long.
Ethanol can cause some pretty serious problems with carburetors since they're exposed to atmosphere, unlike fuel injection systems that are pretty well sealed. The alcohol does increase the rate of corrosion, especially in the presence of oxygen. For most small engines this generally isn't much of a problem because there are no rubber seals like accelerator pumps to go bad. The only ones that do go are the needle/seat if it's made of rubber. That's why it's recommended to shut off the fuel supply and run the bowl dry when storing the engine.
If you can find viton seals for the accelerator pump seals, you'll have a significantly longer life from that carb.