I have well and the water from the well is use for our sprinkler system. I have just ran into a problem my pump is running, but the well water is not coming out unless I prime the pump I never had to do this before. Attached to the pump is well saver tank. My question is does the tank has to be fill with air from a air compressor so that I don't have to keep priming the pump? Well I do prim the pump the gauge goes to 50% does it also need to be at 100%

My question is does the tank has to be fill with air from a air compressor so that I don't have to keep priming the pump?The bladder tank has nothing to do with the pumps losing prime. The correct air pressure of the tank should be set at 2 PSI under the cut in point of your control box. This setting to me made when the pump's shut voff and the system bled down.
As for losing prime the first place I would check is the check/foot valve. Good luck, Tom

Is your pump above, or in the well? If it's above, the pump seal may be leaking and causing the pump to lose prime when stopped. This would also indicate a foot-valve leak. If your seal is sucking air, it will also be weeping when the pump is loaded.

If your pump is in the well, your water table may have fallen a bit, which happens seasonally.

I'm unsure about what a well saver tank is... is it a water sysem pressure tank?

I suspect the gauge is going to 50 POUNDS, not 50 %. If that is the case, then you would not want to the gauge to go to 100 under any circumstances. If it is going to 50# and stopping, then that part of your system is working correctly.

I agree with speedball, it sounds like the footvalve