I believe it is timing, try to retard the hook about 5 degrees and make sure the needle is all the way up before removing material. The hook might be catching the next stitch , witch might account for the 4 threads. Some time it is the looper spring tension its to tight there is two adjustments on this spring , its very hard to explain check the manual for this. Learn your machine its will save $$ Remember when you lift the feet it releases the upper tension , this will draw the thread into the bobbin and wrap it around it.
Last edited by duh57; 03-05-2013 at 10:43 PM.
Reason: second thoughts