The left flipper on my NF seems weaker than the right one. The right one is very loud as the plunger comes against the coil stop, but the left one does not make near the noise and is spongy. I rebuilt both flippers using all new parts, including plunger, linkage, sleeves, coil stops and and new correct (identical) flipper coils. I replaced the left flipper opto board just to see if that had any affect but that did not seem to make any difference and the optos are registering o.k. in diagonostic tests(switch levels.) I checked to make sure there was no binding. Both the left and the right flippers feel the same when i operate them by hand from the playfield. I checked the EOS switch and it is set correctly, opening only at the end of the flipper stroke. Any ideas, thoughts, comments on what I should check next?

Thanks LTG, I will do / check these things and report back.

LTG,
I cleaned the optos on both sides. I added a little more up/down play on the flipper shaft and no binding or drag as the flipper is moving freelywith the PF in playing position. Flipper return spring is new and not binding or hanging up. All mounting screws are nice and tight on the flipper assembly, mounting bracket, coil stop. The plunger, bracket and coil stop are in perfect alignment and the coil is very tight against the coil stop. Played a few games last night and the flipper seems a bit stronger now. I will double check the coils resistance but since it is new, I doubt that would be an issue. All power wires are soldered nice and shiny. Double checked the EOS switch and it opens to about 1/8 inch at the very end of the flipper travel just as the plunger bottoms out on the Coil stop. Thanks for the help. I appreciate it alot. I will keep playing and see how it does.