model 19 problem

[dav 2]

I rebuilt the model 19 for the B-1. it wont fire.

I have checked things out and find that;

the marks on the cam/crank gears line up as per the 'out of production' book.

the arm on the points box is parallel to the side of the box.

the rotor is on the crank right-it is keyed so it only goes on one way.

the problem is that the mark on the rotor to line up the rotor and coil is about 90 degrees away from where it should be when the points open.

i'm missing something basic, i'm sure. any hints as to what will be appreciated