I have a merc 60 with a water pressure guage that comes from the top of the block. I recently rebuilt the engine and the hose that comes from the top of the block to the telltale opening is open as I couldn't find a rubber fitting that was the original part. It necked the hose down to a small opening. Now it is wide open and peeing a stream a half inch in diameter. Won't this change my water pressure reading? Should I try to find a rubber fitting or will this be an issue?