The Talking Machine Forum — For All Antique Phonographs & Recordings

The governor shaft gears are worn and making noise. This is very common, especially if the machine was disassembled, as if for cleaning, and reassembled with the gears located in slightly different relative positions from where they've run together for the last 100 years. You've accidentally stumbled onto the solution, kind of. Loosen the two retaining screws from the governor end bearings. Make sure the end bearings can slide free in the motor housing. With both screws still loose but the bearings in place, run the motor. While the motor is running, place a finger over the end of each bearing. Slightly slide the bearings/governor to the right and left searching for the sweet spot where the noise goes away or at least gets as good as possible. Once that location is found, lock the end bearings in place being sure you have a small minimum end play clearance so the governor shaft is not bound up.

Obviously, care must be taken so as not to let the loosened bearings fall out while the motor is running. If you're feeling leery of this, simply make small right or left adjustments to the governor position until you've got the noise at a minimum.

I moved the governor a few months ago to help adjust the speed, if that's what some of you mean. (I'm sorry if I seem stupid, but I am fairly new at these machines)

Someone also suggested (by email) that the pulley is wobbeling, which means a bent shaft which is causing the problem. What do you guys think about that diagnosis?

If you remove the pulley from the shaft & run the motor, and the shaft is bent, you should be able tell by looking at it.
I'm more inclined to think you have a worn bearing or teeth on the governor as others have stated.
Sometimes if the governor weights aren't balanced properly, it can make the motor noisy too. In the worst case, it can cause the noise to amplify through the whole bedplate & even through the reproducer while you're playing a cylinder.