Tom, a lonely thought, putting a 'backflow prevention valve' or check valve on the suction line would prevent the re-priming problem. If you have valves on the suction lines, close them before opening the pump lid, of course you'll have to open the valves again when restrting the pump - also, only open one line when restarting the pump, then crack the other valve (just enough to draw the air out of the other line without loosing prime) and open it when you are drawing only water.