I recently took over a boat that had been on the hard for over a year. When I tested the toilet, it seemed to work fine--I was to pump water in and then out. However, once underway for a three-day sail, it stopped pumping in water, although it was fine flushing the water out of the toilet. I have a replacement joker valve that I was planning to install as a precaution but now I'm wondering if I should be getting some other part as well. I'd rather just attack the toilet situation once! It's a vintage Groco. The boat was built in 1983.