I just fixed the same problem. First to stop the problem turn off the valve you turn on to winterize. Problem solved. Then change the pump when you can.
Karl. There is an inexpensive repair / replacement check valve kit available. Search for shurflo 4008 check valve. Dont have the number in front of me right now.
Karl. There is an inexpensive repair / replacement check valve kit available. Search for shurflo 4008 check valve. Dont have the number in front of me right now.