shock with 2 fast rebound?

[new2banshee]

I just got an 02 banshee, when I push down on the grab bar it seems to pogo up to quick. I bought another shock off a guy who changed to works, it does the same thing. I adjusted the bottom spin wheel a little to the left, that seemed to slow it down just a hair but it makes noise like it is restricting the gas ( I'm guessing to slow down the rebound ) is that normal? when I sit on the quad I can bounce up and down and it does remind me of a pogo. I quit trying to adjust it until I find out what I'm doing.I have a hard time believing both shocks are bad, and they aren't leaking. My friends 450r comes back up alot slower when you push on the grabbar. Whats the little screw for on the bottom of the shock? please help!! I am getting frustrated! Do I just need to adjust it or junk it? Thanks.