[Doug I]

Sounds like a ground.

Actually sounds like a non-grounding issue.

A bad ground would account for the non-engaging and when it does engage the very slow cranking.

Less likely, but possible, is that the starter has gone bad and not making contact internally when you try to use it.

An alignment issue would sound like some very unpleasant noises as the starter gear and flywheel ground against each other.

I'd check the grounds, paying particular attention to any paint between faces where the starter ground is. Paint on the body is good, on the grounds .... not so good.