If the lower unit was all together, and the power head off, you could place the
lower unit in a deep enough bucket of water and spin the drive shaft over
with a drill, to see if the wobbler pump is still viable.
Hard to tell from your photo, but the center hole of the wobbler needs to
be a snug fit on the eccentric in order to get full contact, and pump water
on it’s outer edges.
Search Brian Wilcox on this site. He makes and sells some wobblers.