When I turn the key to the full start position, there is about a one-second delay before the starter begins to turn over. No grinding or binding and the bendix releases just fine. The only problem is that slight delay, which is new to me. I don't know if the starter is going out or the ignition switch is worn out. 740GL has 223,000 miles and a lot of turned keys behind those miles. Any ideas my friends?

With the car in neutral or park try shorting between the solenoid terminals A and B in the pic below. (easier to see on this RHD model)

If the problem is still there the starter is faulty.
If it turns over immediately the problem is in the wiring or ignition switch.

Colin.

1990 740SE B200E/M47, remote C/Locking.

It could be a loose (or corroded) wire on the starter solenoid. The starter solenoid is a electromagnet and must develop a electrical field to magnetize the core. Anything that slows down the flow of electrical current slows down this process. Check the wiring and connections first.
Steve

Thank you Colin UK and Hillbilly. Great ideas. That what this site is all about. Thank you Brickboard!