timing on yamaha 4 stroke gas golf cart.

I bought a yamaha 4 stroke gas golf cart for my two boys.I replaced the battery in it with one that has side and top posts needless to say my boys took it up on two wheels making the side posts of battery short out on the side of cart where battery sits causing it to short out and it melted the gear cables where it shifts from forward to reverse melting the black plastic coating off of it so i replaced cables and now it tries to crank but it back fires instead i think that the place in back where cables hook up has something to do with timing but not sure if anyone has a suggestion please tell me i am open to all opinions thank you.