Portable air comp not working properly

HELLO CAS! I replaced the pressure switch today on my Speedway Series 2hp 8 gallon compressor. When I turned it on it ran great and filled quickly - when I let air out to check the back on pressure setting, it tried to run but stalled as though it had to much head pressure. It kept trying but I feared damage was possible so I turned it off and drained it. When I turned it on again the exact thing happened again. So what does your professional experience say it is? Tks Stewart