There is no fuse for the lift motor on this model of lift. Most likely you burned out the lift/hydraulic motor. If it was an over weight that would explain why the whole unit it was killed. It is possible that the batteries are also experiencing issues after drawing too much amperage or there is additional damage inside the lift.
The weight limit on forklifts is something that should never be exceeded. More modern lifts have better protections, but these older models do not have many protections at all.