I know you guys sew so I thought I'd run this problem by.

I just Picked up a new to me singer 750. While in the process of threading the bobbin I noticed the needle bottoms out on the turning metal plate below the bobbin. From what Ive been able to google, Ive come to the conclusion that the machine is out of time? Is there a sewing machines for dummies guide out there? can anybody share some knowledge on how to get my machine running right? thanks!