pinkcastle,
You got a sweet little 3/4 sized machine. The 99 and 99K differ only in that the "K" model was made in the UK. Otherwise they are the same.
Before you really get to using it, clean the bobbin area well by removing the bobbin carrier and cleaning everything around and under it. Clean the top tension too. Unless you have problems you don't have to take the top tension apart. Basically just make sure there's no gummed up oil, gunk, stray threads, or lint stuck between the tension disks and that the adjuster moves freely.
The large needle probably had a bur on it or was bent. It could also have been the wrong type needle. The 99s use the standard 15x1 needle or Singer #2020.
I have two of them. The first is named Godiva as in "Lady Godiva", her story is here:
http://www.quiltingboard.com/vintage...r-t183512.html
The second is named Rusty. His story isn't finished yet, but there is several posts discussing some of his problems here.
Joe