I need help. I hope someone with insomnia can respond to this tonight so I can fix my head tomorrow. I have a jabsco manual marine toilet, when I put the lever on wet, it won't pull any water into the bowel. I have the through hull open to bring in lake water but no water can be pumped in. The bowel will pump dry easily. I can pour water into the bowl and then pump it dry. I went to west marine today and they said it probably was the joker valve. Does it sound like that is the problem? I hope so because that would be relatively easy to replace. Any suggestions would be appreciated. Since it is late now and I am going to my boat early tomorrow, any responses would be great. Thanks Mike