I'll keep an eye on the motor on the FW I'm using right now, and report back. I'm about to do some sewing. However, the motor on my 1951 gets a little warm when I've been using it for an hour or so. I do try to take breaks. I've switched to a 1938 machine and I'll let you know how it does.
In general, though, I don't think the motor should be hot.
Ila