If your Featherweight isn't sewing as fast as you'd like for it to, try setting the hand wheel to wind a bobbin (to prevent needle motion) and running your blow dryer over the motor while the machine runs. It loosens buildup and you'd be amazed at how well it works!
This machine arrived in such poor condition that I chose not to resale it without a total makeover. It was a lot of work to remove and replace all the parts to send it for paining, but in the end I was extremely happy with the outcome and the effort was worth it!
If you're Featherweight motor has a slow start or sounds like it's working too hard to get going, don't assume something is wrong with the motor. Try loosening the motor screw and raising the motor until the belt is lose enough to grab and turn the hand wheel (but not so lose that it has trouble engaging). Beware of lower quality belts which can lead to frustrating issues with slipping.
After discovering an interest in vintage machines mostly inspired by members at my local quilt guild, I bought a couple of Featherweights in Wichita, Kansas and Dallas, Texas.
These machines are sturdy and easy to clean and repair if you're willing to invest the time and some $$ for supplies.