Jerk and stall when put into gear?

I think you'll find timing problems. The outer ring of the crank pulley, which has the timing mark on it, slips relative to the inner hub. Then if you use the timing mark to check the timing, you wind up with the timing much too far advanced. The engine will run with no load, but apply a load and everything stops working. So…check to make sure an indicated 0 via the timing mark is in fact TDC on the frontmost cylinder. See here. See also here.