I hauled the boat this weekend, and while I waited at the lift, I disconnected the head. Went ahead and removed the pump to check the joker valve and sure enough it was open and gasping. As big as the gap was between its lips it looked more like a choker valve. There was the source of my backflow problem just as you had predicted. Drove to WM and bought an HF rebuild kit and had the entire job done in about half an hour. Didn't have any teflon grease, so I didn't reinstall the pump. Is lithium grease with teflon suitable to lube the pump plunger? What about petroleum jelly? You've probably answered that a hundred times, but I was ready to slather on the Petroleum jelly until my good angel reminded me to check with Peggy. Hope your move is going well. Tom Ehmke