1991 Honda Accord 1992 Honda Accord won't turn over

So, I've had this beauty for about 6 years now. Over the past year, its been having problems turning over. It cranks and cranks, but nothing catches. This always happens when the car is hot (has been running for a while and I turned it off to go into a store. Or has been sitting in the hot sun).

I took it to my mechanic, and they replaced a part that attaches to the alternator which was producing low spark. This has not solved the problem.

I've seen a few discussions where it this can be linked to one of the following problems:
1.) Leaky fuel injectors
2.) Main Relay
3.) Need extra air in the cylinders (so hold the pedal halfway down when starting)
4.) Starter is heat soaked (causing to much internal mechanical resistance)
5.) Ecm needs to be changed
6.) Ignition switch

Do you have any suggestions?