vanginney,
Pull off the face plate, just loosen the screw at the top, lift it straight up and pull it off. Then clean and oil everything in there.
Also if you see a hole without threads oil it. Pull the plate off the back and oil everything in there. Pull the hand wheel off, just one little screw too loosen then take off the stop motion knob and the clutch washer and the hand wheel will come off. It might need oil and encouragement, but it will come off.
After that, tilt the machine up on it's hinges and oil everything underneath that moves. Lots of little oil holes under there, but if you can't see them oil it all. You can let the excess drip off or wipe it off. Put a couple layers of folded up paper towels under the machine to catch drips.
It didn't get gummed up over night, so it can take a while to free up. Just be patient and keep working on it.
As for the belt, don't make it too tight. I should be just tight enough to not slip. Make sure there's no oil on the belt grove of either wheel, they'll slip like crazy if there is.
Oh, I'm not bragging but my treadles are so easy to turn I can belt them up and turn the machine and treadle parts with one finger through the hand wheel. Easy is an understatement.
Joe