Mickey2

My trick is to oil often, let it seep in, wipe off any excess, keep on oiling and running the mechanism now and then. It will loosen up the mechanism and any gummed up parts will clean up with patience and a bit of effort. You can speed it up by using spray can oils, kerosene (smells), but any good oil will get you there. I like TriFlow but use what you have; keep up a tentative oiling routine the next week or two, and it will not gum up so fast again. Mop up best you can between oilings and running the machine, cotton rags and swabs work well. Don't be afraid to unscrew the needle plate and top of the free arm, also inspect behind the lid in the back (at least few gears on the horizontal rod and probably on the cam mechanism). Use correct size screw drivers and be carefull not to scratch anything. Oil all the moving parts behind the face plate, including the shaft where the needle and presser bar moves. Detect all the oil points, there is one behind the motor / belt cover, four holes on top, hook and race, etc. It might take a couple of days to free it up, and yet a week or two to flush out and replace all grime and dried up oil with fresh. The best thing you can do is to start using the machine as soon as it runs reasonably well.

Best of luck :- )