Fuel pump

If you've been out of service that long, during your annual ( possibly not completed yet) the fuel pump should have been serviced/inspected per AD 81-07-06. Possibly the restrictor in the pump output is plugged. With caution, you could loosen the fitting and have someone monitor with a brief engine start - fire ex standing by!!!!! Another point, if you had MO gas and happened to get alcohol and it sat that long, your rubber diaphragm may be bad. 2c

I'm just returning my 415-C to service. It has not been started in a couple of years. Today I did a long taxi and run up and noticed the header tank was going down. My question is can the fuel pump loose prime after not running for so long and is there a way to prime them?
It is a low time pump and worked fine before storing it.
Kenny