Many times the governor is the cause of uneven running. Check that the governor shaft isn't gunked up. Might just need to be cleaned so that the governor sliding collar moves freely. If the collar doesn't slide easily, it will cause uneven running.De Soto Frank wrote:Pathéphone VII. Could never get the motor to run evenly.
Remove the governor. One end of the governor weight assembly is secured to the governor shaft with a set screw. Loosen that set screw and the weight assembly should slide right off the shaft. If the shaft is gunked up, it may not slide easily. Clean the shaft and clean the inside of the sliding collar and put the assembly back on the shaft and tighten the set screw. Be sure to note where this assembly is located on the shaft and try to get as close to that location as possible when reassembling. Reinstall the governor and it should work better.
Also make sure the disc on the sliding collar is smooth, free of bumps and such. Last, keep the speed adjust pads oiled.
Cliff