sailor said:

I have an older Unisaw with a 1 hp Bullet motor.

It started acting up today. When I turn it on, it runs at reduced speed
for about 10 seconds, then kicks in to hi speed.

Sometines when it is turned on it just makes an unhappy hum. I then
rotate the blade a bit, and turn on again, and it starts and runs at
reduced speed for about 10 seconds, then kicks in to hi speed.

When it is running at reduced speed, the brushes (lots of brush left)
arc a bit. When it kicks to hi speed, the arcing stops. I think the
brushes might be just for starting.

Anyone familiar with these motors, and have an idea of the problem?

Not familiar with this exact motor, but the construction is generally
similar to all induction motors.

I would check the start cap - it is probably leaky.
The "brushes" you refer to are probably the centrifugal start switch.
Both are removed from circuit when the motor reaches a defined RPM.

FWIW

Greg G.