I have a carbureted motorcycle and the guy who had it before me had to have the carbs rebuilt after letting it sit over a winter with ethanol containing gas in the tank.
I use Seafoam gas additive to help prevent this problem and my bike has been trouble free for 3 years, 2 of which were bad winters where it sat unused for 4 months and started right up come spring.
I am sure other additives will work as well, but even with ethanol free gas, you should add a treatment / stabilizer if you are going to let the carb sit for an extended period of time.