sear 390

i have a sears 390 pump which was working fine until i had to drain the lines to install a sillcock. the house had no shutoff valves. now i get little water pressure. i have removed the pressure gauge and primed the pump, to now help. what am i doing wrong?
thanks

Prime it again and again.... you need a bigger hole than that through a pressure gauge, and you might need several gallons of water. crack a valve on the outlet for the air to vent out....