I have an 84 GSL-SE.

My starter died.

I pulled it and took it to the parts store and had them bench test.

It was DOA.

Bought a new one and installed it.

First crank, I heard it spinning but that was it.

No engine movement or start.

Sounds like the starter teeth are spinning but not engaging.

What did I miss?

 

I'd remove the new starter and bench test it or take it back to where you got it and have them do it. Sounds like the motor is spinning but the bendix isn't moving and the the piñon gear isn't engaging with the flywheel. Your new starter is just a rebuilt unit and could be defective. This just came up in another thread. When your starter goes out, you're usually just as well off taking it straight to have it rebuilt yourself. The only downside is it might take a few days to get it back.

 

Had them bench test it before I bought it.

Watched the test myself.

Starter passed.

 

There is a trigger wire that activates the bendix. Assume its attached and has power when activated?

 

I've reconnected the box connector to the blade, and screwed the power to the bolt.

 

My other question -

The starter has been working until yesterday when it stopped.

Pic 1 is the original starter before I pulled it. The solenoid is inboard.

Pic 2 is the FM image of the starter. The solenoid is outboard.

Pic 3 is the new starter.

I installed the new one as the old one was positioned. Is it installed wrong, does it matter?

 

When installing the starter, the open portion where you see the gear must face inward.

 

When I put this starter in it spun but didn't engage.

Took it back out.

I guess it looks good.🤷🏾‍♂️

I bought it new and made them bench test it before I left the store. I'm guessing that's where the yellow stuff came from.🤷🏾‍♂️

Inside the housing and the teeth look good.

Thoughts on why it's not engaging?

 

I don't think you can install it backwards. The backside of the housing would contact the flywheel and not allow it to locate properly.
You should be able to turn the gear by hand and extend it out like its engaging. Have you checked the trigger wire for power when you turn the key to start? If the starter works on the bench, that to me would be the next logical thing to check.