How do I keep the terminal from becoming red hot when I hook a motor to a battery?

You need good quality connectors with lots of surface area. Your wires need to be quite thick: think solid copper bars, instead of stranded wire.

By the way: a car starter motor is designed to run for only a few seconds at a time. A car battery is likewise designed to provide starter motor current (which can easily exceed 100 Amps!) for only a few seconds at a time. If you're using the starter motor to drive the go-kart wheels, you won't get very far before either the battery dies, or the motor melts.

With the losses inherent interior the motor and the alternator, the battery will steadily bypass flat. truly a motor itself places some potential again into the circuit, it makes use of plenty to commence yet them the quantity of cutting-edge drops significant because it runs. i'm no longer particular what your question has to do with automobiles and transportation even if.

Automobile starter motor is designed to run continuously for short duration only, preferably less than a minute. The instantaneous current drawn from the battery is very high, hundred of amperes. Large amount of electrical power is needed to generate enough torque to crank the engine to start.

It is not suitable for go kart purpose. Use a miniature DC motor instead.

A hot terminal means either a bad connection (high resistance) or a very large amperage. Motors do pull 7 times steady state amps at startup but that only happens for a few seconds. If your motor is overloaded or is faulty, it may be drawing too many amps. I think it is a bad terminal connection. Make sure your motor is not loaded until it is spinning near steady state RPM. If it isn't heavily loaded and in spinning near steady state RPM and the terminal is still very hot, that implies very high current going somewhere else than to spin the motor.