I took a close look at everything and what I think is wobble is really the edge of the paper tach tape. I took a sharp Xacto blade and trimmed the edges down and it appears to look better now.
I don't recall (would have to take the tach tape off to determine) but I don't think I had to put a setscrew in the flywheel, it's just a press fit. I have another flywheel (bought 2) and it doesn't have a setscrew.
I need to look at the boiler shell to make sure it's not causing the sound I'm hearing. I have a thin sheet of sticky-backed craft foam inside the boiler where the drive is to help quiet the noise. I don't see any marks on the foam that would indicate something rubbing on it but there may be something else I'm missing.
At top speed there's some vibration felt on the motor, but I think it's normal and not the problem. I do have 2 rubber traction tires missing on the same side so maybe that could be causing at least some of the noise.
I'm going to put the boiler back on tomorrow and see if the sound increases and try to locate 2 tires to put on.
