You just need to rebuild the flipper. It's not the last resort. It's a must for just about any game i do.
Check the resistance of both coils. That will tell you what you need to know there. You have to open the EOS to check the hold winding.
Most assuredly the spring is not causing a weak flipper situation.
I concur with Lee that not only is the EOS open it appears to be missing a contact.