pump motor problem

I have an old (circa 1952) motor jet pump system. Motor rotates freely by hand. Replaced two starting capacitors and thought that would fix the problem. All I get is a buzz, and sometimes very slight movement in the shaft. This is a Fairbanks Morse 1HP motor operating on 220. Access to the internals seems pretty hard. Are there brushes or any other wear parts in this kind of motor? Any advice would be appreciated. This whole thing is rusted/gunked in place and I'd rather not have to dismantle the whole system. Thanks.

Somebody who really knows about these things may correct me, but every capacitor-start motor I've seen has some way of switching the capacitor in and out of the circuit. It's usually a mechanical switch activated by the speed of the rotor as the motor comes up to speed -- there are weights that are thrown outward by "centrifugal force" which move the switch contacts. If your motor is truly gunked up, corroded, etc., that switch may be stuck in the "run" position, contacts could not be contacting, etc. These switches are not generally easy to access.

I once worked on a garbage disposer with the same symptoms. Cleaning the switch cured the problem, but when the homeowner saw what her disposer looked like "all gunked up", she elected to replace it.

Thanks for your suggestion. I started to work my way into the motor but the bolts and the case were so encrusted with rust and gunk that I decided to put this 56 year old system to rest and replace it with a new one that I hope is equally reliable. Even half as reliable will get me through my needs.