[Gaz64]

There two terminals on the starter.

Leave the big battery lead off the starter (insulate the terminal temporarily) and just have the small start lead connected.

These two leads are side by side, the other side (under the blue cap) is the motor winding side after the solenoid contacts.

Operating the starter should then allow the pinion to mesh, to check all of the necessary clearances etc.

Don't even think of operating the starter until these measurements are correct.

Pinion mesh depth axially and radially must be correct or noisy and failure is the result.

They also don't like lots of ignition timing that might cause starter kickback.

Gary