ds247, it sounds like you are describing a motor like that at
http://6L6.net/bjarn/6R13.ecn.WWG.p109.catalog.pdf with the fan blade mounted directly on the shaft.
An SF (service factor) of 1.0 means that the motor can’t run with any overload for much time without damage.
I’d make sure that the installed run capacitor matches the one called for on the motor label. Also, check voltage (at the motor) to see if it’s OK.
Try taking off the fan blade and checking the motor’s amp draw. It should drop below 3 amps.
