When I was working on my Grandmother's sewing machine a while back, I used the brown lubricant shown below. And, it just never quite worked right. Sure, it went in the machine, but whenever I used the machine, it sounded like it was in some kind of a bind and the motor was working harder than it should. So, I decided that if I thought the lubricant was bad, that was a good place to start looking for the problem. So, I bought a new tube at JoAnn's, where it is actually readily available on the notions aisle. Who knew??
This mornging, I opened up the plugs, pulled out the wicks (if you have an old singer, you know what I'm talking about. If not, imagine opening a small jar of brown vaseline and pulling out a piece of shoelace, a spring and a metal clip. Gross is right!) I cleaned the wicks, replaced them in the springs, inserted them and added the clips, filled the reservoirs with new, clear lubricant and replaced the covers. I stood the machine up, pressed the gas and it still sounded like it was working too hard...but only for a second. Slowly it began to speed up and the movement got smoother and faster and faster and faster.
Now, she purrs like a kitten. I'm thinking about disconnecting the feed dogs and FMQ something with her. Whoohoo! Way to go Mary!
Problem solved. Key lesson learned? Sewing machine lubricant, like sewing machine oil should be clear, transparent, almost invisible.