Thinking it was the line and fitting, I got new parts at NAPA, but the leak was still there. I ran the engine with the instrument cluster setting on the steering column and observed the leak source. The NAPA guys did not have a replacement fitting that screws into the gauge. It has occured to me that the o-ring has been squeezed to obstruct the passage, but am not inclined to remove it until I have a proper replacement. I think a thin copper washer like those used in carbs would work, but the NAPA man had never seen one that small.
