Things getting wet can cause issues. Thankfully, most of the time after a day or so of drying out, the problems go away and the cart is fine again. Otherwise, you may be blooming at something like a solenoid or possibly the micro switch they're activated by the throttle, but let it get good and dried out before you worry about having to replace parts. One thing you definitely want to do tho: put a proper battery hold down in there. Loose batteries are a recipe for (eventual) disaster. It may not happen right away, but you will end up with broken cables, arcing, and/or exploded batteries, and that's not fun for anyone.