My Timing's off...

I was talking to the lady at Joann's yesterday about my sewing. I can't figure out why my bobbin thread skips and bunches sometimes. I've thought maybe I've been doing something wrong or using the wrong type of needle. Sine I'm pretty much self taught, I have been frustrated trying to fix my errors. To my relief she said she thinks it has nothing to do with me (YEAH) and that the timing on my machine is off and I should take it in to the local guy to get serviced. I'm going to try to drop it off this week. Luckily I just got my backup machine back from my sister, so I'll set that up to try to get some stuff done. I promised a friend that I would make some things for her La Leche League fundraiser next week, so I need a working machine.