Hi Robm,
With the machine switched off, can you move the flipper freely (from underneith) by hand? If not then it may suggest something is binding?
Edit - couple of things, that coil stop looks to be on an aweful angle...I suspect that may be a problem as the coil is not sitting square with plunger.
Also, the coil lugs (wiring) should be at the opposite end as the coil stop has the most vibration...
