Just bought a taotao tforce for my son. Underneath the atv there’s two bolts for emptying fluids. One is obviously for the oil. What is the other one? I accidentally unscrewed it and some fluid came out along with a spring. I put it back in but need to refill whatever fluid that was that came out?

also, after I put it together, the remote control will start it but when I press the start button on the actual atv it does nothing. Any help would be appreciated! Thanks!