Head odor
Gary, I had the same difficulty trying to follow the hose to the vent fitting. I was trying to check the vent because 1)I was getting an odor in the head, and 2)there was a lot of back pressure when pumping the bowl dry. Initially, I figured that the vent was clogged, but it turned out otherwise. I checked to see if the vent was open by pumping the head vigorously, and then quickly pulling the vent hose off of the tank fitting. There was no rapid escape of gas. When I tried the same with my finger over the tank fitting, the tank held pressure until I removed my finger. I eventually decided that the smell was coming from stale water in the head inlet hose. Others have reported the same problem. After I pump some water through the head, the smell dissapates and does not return until the system has been left unused for another 24 to 48 hours. Every time we open up the boat, I try to get the stale water pumped out before my wife or passengers get a nose full of that nasty smell. The back pressure was another problem. It turns out that there is a flapper valve in the pump which is supposed to be opened when the switch is moved to the "dry bowl" position. The switch was not opening the valve, and that caused a vacuum to build up behind the plunger on the down-stroke. Check the attached picture for a simple way to extend the lever. I would like to hear the manufacturers response to this problem as I know several owners that have the same experience with the Jabsco model that was used on the C320. JC
