Also, realizing I could be wrong too, in that the lower or down limit switch is maybe the one that needs to be the lighter force to actuate? In an "ideal" world, we want them both to be equal, but if we have to pick and choose, I could have been wrong in my previous post which one was more critical to operation.
The theory is, the cam is dragging on that lower limit switch at the exact moment the solenoid is weakest trying to start pulling in the plunger and lifting and accelerating the platform. The upper limit switch is hit by the cam at about the halfway up point, but by then the system is already moving, the solenoid is in the stronger state of pull just before the upper switch turns off the coil.
So really, drag in the beginning of the cycle is a huge part that determines the voltage required to fully actuate up. Down, we are helped by gravity, but up is kind of the killer state.
Further, the spring and it's adjustment are there to hopefully counteract the effect of gravity pulling the platform down. I noticed this when manually moving mine just now, you can feel the spring and the tension trying to counterbalance the weight of the moving passenger platform. It should be neutral.
