Ralph,
Your previous posts indicate your starter is a key switched solenoid type. When the key is turned to START and the solenoid energizes, it drives two copper discs together at the end of its travel. This is the switch that powers the starter so it will spin. You say your starter just goes 'clunk'. Is the starter actually trying to turn or is the starter drive just blasting into the ring gear properly but not closing the switch and spinning the starter.
Have you pulled the starter and cycled it on the bench with a battery or charger to see it pull in and spin. These are two separate operations.
Stuart