While getting the tiller ready to do some work in the garden, we noticed that the gas tank had gotten a fair amount of water in it.... and now is running very poorly. We have to giggle it to keep it going.... What can we do ?

drain the gas tank and refill with new gasoline

yes, drain the tank, flush the carb out with some cleaner if you want to, and refill with fresh gas. and throw a little high concentrated rubbing alchohol in it, not much but it'll suck up the water and make it burn easier, it contains water but it also burns blue. don't use much because it will boost it a little. maybe 4 capfulls or 5, oh and not the green colored, the clear