My '96 F-150 XL 6cyl is not turning over. I thought it may be the battery, so I began to check the battery cables making sure they were not loose. As I began to inspect the cables, I touched the positive cable and it was very warm, and I also noticed a burnt smell. The starter is very warm as well.
Should I proceed in replacing the Starter? Thanks....

 

The starter can be tested - suggest to do that before a blind replacement. Yes, the starter could be bound up, but always recommend to test and verify.

If the cables are hot - suggest to check your connections, including the grounds. Some cables have a tendency to corrode under the insulation where it's not visible, suggest to slice the insulation about an inch or so back from the battery connection and inspect. If OK, then tape up good.

 

Thanks WDE, I had the starter and battery tested this morning at Autozone. Both passed. I received a starter test result sheet with recommendations, one of the suggestions was to check the belt tension. Turns out the A/C compressor was seized. The belt was unable to turn because of this. I guess I'll be replacing the A/C compressor next. That test result sheet really came in handy.
Thanks.