Hi Dan,
Thanks a million for the tips. It's a done deal. The compressor is mine so I will run the tests with my fingers crossed. As you might imagine the price was very reasonable so it won't break the bank if this turns out to be a bad purchase.
The motor is a huge old 2 horse 3 phase unit. It was also made in 1948 so perhaps original. I will have to find a good single phase motor before using the compressor but can run the tests with my little Emglo Airmate.