Motor is a FASCO set up as a Sears attic fan made in 1967.

The old cap was bulged out. Measured 27uf and it should be a 10 uf.
Symptom was motor would start ok and run hot eventually turning off. then clool down a few seconds and restart over and over and over.

I had a 5uf run capacitor handy to try (measures 6.7uf) and so far motor is running cool, and has kept running, and seems to blow air fine.
Any reason not to use that cap instead of spending money for a 10uf?

Other thing, motor mentions to oil it every 6 months. I dont think its been oiled in 55 years. And it spins smoothly.

 

27uf seems high for a simple fan, I would peg the average one around 8uf.
If the optimum value is not used the motor Will run hot due to wrong phase shift angle.
Max.

 

It says 10uf on the bulged cap, but it reads 27uf and motor overheated.
Motor is stamped for 10uf run capacitor.
It is a good looking quality motor and fan. Must be good to have lasted so long.