Help With SkiDoo Brakes

I'm having troubles with my sons 98 summit 500 brakes. I cannot get them to hold pressure. I have bleed and bleed the system. I can see the piston move but when I squeeze the brake handle it goes right to the grip. I did notice the lever has a lot of play before it begins to engage the master cylinder pin. It like the master cylinder pin is not retracting all the way back out. Any help would be appreciated.

Thanks.
Ii just ordered s used master cylinder to see if this works. If not I will continue with running through the rest of the system.