The blower motor is a belt drive 1/2 HP 115V motor with start capacitor attached to a squirrel cage air handler. It does not consistently turn on in the auto mode and has to be cycled a couple of times in the manual mode to get it to turn over. I have checked for free turning of squirrel cage air handler and motor separately and found no problem. I have replaced the start capacitor with no change in results. I have it running in the continuous "on" mode.

The problem occurs when actuated from the thermostat, the emergency switch at the furnace or the "manual/auto" setting on the furnace heat switch.
The furnace is an old "Mueller Climatrol" furnace with a A/C evaporator.

Any other suggestions?