Got a little problem here and I need some ideas. When I turn the key in the ignition, it cranks fast, then slow (very slowly), then usually starts. Sometimes it cranks fast, then slow, then fast again. I had a two battery setup and thinking that had something to do with it, I removed both batteries and replaced with one brand new one. After I put the battery in, it cranked fast, then slow again and finally started. I've read in other posts that this could be a symptom of a couple of things...bad starter or timing too far advanced (?). Question is...how dow I go about diagosing what the problem is? My thoughts are just replacing the starter... Thanks!