You may have to use something stronger than Tri-flow. If you do, be careful to protect the paint. BUT I would just try the tri-flow first. I'm amazed at what it will do. Some times you do have to turn the machine so oil will go where you want it to go - for what ever reason oil flows down better than sideways or up...
Some times it takes time. I take the rubber parts off and heat it gently with a hair dryer after the oil has flowed in a little. Grant says to put a drill on it and try to turn it. When you are done replace the bobbin winder tire with a new one. I have found (the hard way) it doesn't pay to get in a hurry when you work on sewing machines OR when you sew...
The fly wheel may be ok some times if you put the nut on wrong it can act up but Rain has a very good description of how it goes together. I love his blog!