One of the last mechanical problems on my F14 is the upper right VUK ball popper.
- About 20% of the time it kicks it hard and straight and the ball quickly flows off into the tray on the left.
- Another 25% of the time, it kicks it up and the ball trickles very slowly finally making it in the tray.
- 5% of the time it kicks it up and the ball can't make it to the tray and slides back down into the shooter lane.
- The remaining 50% of the time it takes 2 to as many as 5 kicks to get it up -- with the ball not making it out of the vertical portion of the wireform.

Things I've tried to improve it:
- Zip tied the VUK wireform to the ball shooter wireform in the middle. This lifted the shooter form and slightly lowered the VUK one so that a slow kick tends to have a better shot at getting to the left side (more angle of decline when dropping, less angle of incline once dropped)
- Moved the angled plate on the back of the VUK hole as far back as possible to ensure it's not hitting that
- Realigned both metal side lane guides leading to the VUK (pushing as far out as possible next to it)
- Slightly shifted the VUK wireform
- Completely disassembled and cleaned and rebuilt (new coil sleeve, spring, coil stop) the VUK assembly.
- Made the activation switch more as well as less sensitive

My best guess is that the ball hitting the catch is just enough to trigger the switch but the catch hasn't fully 'fallen' onto the base of the plunger / sitting at an angle, and therefore when it pops it binds against the wood or loses some of the kick. However one would think it would take at most 2 kicks then given how hard the ball falls back on it after a failed one. But the top moves nicely and I don't notice anything when testing it by hand, and without a high speed camera, it's hard to tell exactly what's happening when it doesn't work.

Any ideas to improve this? It really makes for getting the 3 landings during multi-ball to win the jackpot hard, when there is a ball constantly being kicked with no room for a second one

PS: SIde question since I mentioned shooter lane: Why did F14 have a red colored (high tension) shooter spring? I found that very annoying (and apparently the cause of some cracking on the upper left diverter tray at the impact point), so I replaced it with a used plain silver one that has even less tension than a new one, and the game works perfectly fine that way and could even go at least one lighter on that I think. Anyone else experience this?