Morning update - STILL NOT STARTING

The starter was faulty - there were two solder points in the starter motor that needed to be re-soldered. The shop fixed it, and I watched them re-test.

Installed the starter. Check all the voltage:
12.8v in the battery
At pre-glow, 11.5v Battery Neg to Starter positive, 10.8 Battery Neg to Glow Plugs, 11 Battery Neg to GP fuse.

Attempt to start - just a clunk. I assume the starter is engaging but not turning the flywheel. With that voltage, shouldn't the starter turn the flywheel? I tried 5 times and stopped. I also tried with jumper cables to another car.

What am I missing here? I'm in Florida, so its not cold. Fuel supply and compression have never been an issue. It was running strong a week ago when the starter went.