Hooray for Vid!
I, too, had sluggish pop bumpers on a Surf Champ. I had done a full rebuild, including the switches, polished the rings and rods, straightened and squared the rods, re-centered the spoon any number of times, all to no effect.
Then I re-watched Vids rebuild guide, and realized I had the washers on the wrong end of the threaded rods. I had them directly under the nuts. I moved them to the base of the threads, reassembled, and it was a night and day difference! They are really peppy now. The devil's in the details!
Thank you Vid, and thank you Pinside.
Jim