Ok so I bought a 6 volt battery and installed. The hookups fit one way on the battery. So neg is smaller than positive. My dad might have modified. Nif not it seems like this is a positive system? Can the engine be ran backwards? Another question, which way is fan suppose to turn? Just making sure. If I stand at the front, the fan is turning to my left? Any insight would be useful. It did kick over a couple of times by the way.