Will the flippers propel the ball to the top of the playfield?
The first thing I would suggest is to examine the wires that connect to the flipper solenoids and make sure that none are loose or broken off at the solder joint.

I once helped a fellow with a Bally Nip-It who reported both flippers were weak after the game had been transported. It turned out that both flippers had the same wire connection to the solenoid (the shunt wire that short circuits the hold coil) fractured off at the terminals. Easy fix in that case.

It looks like maybe those loose and poorly connected wires go to the end of stroke (EOS) switch! If so, that is what I was writing about in post #2. If those wires are disconnected, the EOS switch becomes non functional and the low-power hold coil remains in the flipper solenoid circuit, which then results in low current (or low power).

Read about flipper function here, especially toward the bottom of the section: http://www.pinrepair.com/em/index3.htm#flips

From looking at your 3rd photo in your recent post, it appears that the prior owner did a very poor solder job on the wires to those flipper coils. I see several big, dull-looking globs and one that looks cold soldered. Once you become proficient with soldering (or get some help), I would strongly recommend those wires all be resoldered.

Lee