MaggieLou - you did not mention if you were using the prewounds for embroidery or quilting. I also have a brother embroidery machine and the way I understand bobbin threads is that you use the bobbin holder with the colored dot for prewounds and the one with green paint on the tension screw for all other weights of thread. (Sometimes it is pink paint not green.) My prewounds are 80 weight and they work fine in my machine. I also have a spool of Brother bobbin thread for winding my own that is #60 weight - but I haven't tried it so cannot speak to that. In my classes for my new machine they taught bobbins this way - with the most important part being to change the bobbin holder for the type of thread being used. For embroidery I use the prewounds, for everything else I drop in the other bobbin holder and everything is great. Also, do you have a "washer" that you use below the prewounds? Prewounds are on a thinner bobbin (height) and the "washer" raises it up to the right height to feed correctly. Mine is metal and has a plastic spindle that pokes up through the center hole. Sorry - I don't know the correct term for what I'm calling a washer. I do know from experience that prewounds without the washer create a mess! Hope something here will help.