wires / motor overheat

[campbuds]

Ok, so I do not have the items in question in front of me. But if it makes a difference I will get the info and post. In the mean time...

One motor was causing much interference, so I soldered on caps. and off I went. (it is a older motor from the late 80's / early 90's "speed works" I believe)

The motor got so hot it melted the solder on the capacitor to motor housing.

So, I tried a newer motor. Still slow but this time when throttled I lost steering (unlike with the other motor). So I dropped a fresh battery in a ZOOM! I was booking. (this motor is a 8T motor which is the limit of my SC)

But this time the battery wires were really hot!!!

What is going on here? Why can't I run stuff without so much heat it may cause damage?