Champainer,
Question; do you have an owners manual? The threading of the WW D9 or Singer 9W-7 is different from most other machines. And ... they rotate opposite from all other Singers as well. So if the machine is not threaded correctly the tension will not be right.
Here is a pic of a manual that shows the threading on an earlier machine than my two. Let me know if yours is different as I have some more pics.
[ATTACH=CONFIG]457311[/ATTACH]
It's fairly simple but does vary from WW9 to the Singer 9W-7 a bit.
I have other pics of the later top guides too if you need them.
Joe