If the unit has been setting for a long time you would need to start with re-exciting the field.
If this does not resolve the problem the first check the winding for short to grounds, also check the resistance readings.
If these are all ok and within specs... then you will need to check the diode.
You can find a service manual at www.msservice.net
the rating for the capacitors is printed /imprinted on the capacitors
take them along with the information you have given to a electrical motor rewind shop and they will match them up
Out of the bottom, condensation will gather at the lowest point. If you put the drain up high, the tank will fill with water and reduce the capacity of the reserve air.
