Why is the fuse blowing?
Motors generally blow fuses because of a shorted winding. It makes them draw more current, but they have less power.
Why is the fuse blowing?
There is short circuit in the system
Rectify it
fix the low resistance path.
check the polarity are the batteries in the right way?
the description go cart is pretty vague but for his i will assume it is some sort of remote controll toy, the only reason for the fuse to blow is there must be a fault that allows too much current to flow.
Has it got wet try if so let it dry out or spray some oil onto the electrical components not the fuse holder otherwise all you can realy do is visually inspecting the wiring for damage or metal debris.
if you have a multimeter set it to ohms scale and test between positive and negitive before you do anything this will give you a base reading of the fault try some of the above things then test again the reading should be higher.
