Did you check the terminals to make sure they have not corroded? I recently fought a similar starter problem - turned out that there was a bad cell in the battery. You could charge it and it would start for a couple of days and then go bad. Take out the battery and have the parts store put it on a load tester to see if it is good. My advice on batteries - get an Interstate - stay away from the big national auto parts chains and take note of the date that the battery was manufactured. I had a parts store tell me that a battery that has been in stock for 6 months plus should be avoided. I had a bad experience with Schucks - when the third starter went bad in my street rod in 2 years, they tried to give me another new replacement battery off of the shelf. Before I left the store, I asked them to load test it and it failed - right off of the shelf!!! They did do me right by giving me a new gel battery. Always have them load test a new battery before leaving the store.