I have a 2 year old Jabsco 29090-2000 manual head. When flushing, the bowl empties but then "squirts back" when it is almost completely empty (not pleasant). I changed the joker valve which was covered in scale (??). It flushes better but still back splashes at the end of the flush. Otherwise, everything seems to be operating properly. This is in a 2004 Hunter 41 in Key West. Any ideas?
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A couple of possibilities
A blocked tank vent will pressurized the tank, creating backpressure that'll cause a toilet to spit up. Check the vent thru-hull and the connection to the tank--both the fitting and that end of the vent line. If your joker valve was scale (sea water calcium carbonate) encrusted, it's a good bet that there's also enough buildup in the head discharge line to reduce the diameter enough to create back pressure that'll cause a toilet to "burp" or spit up. On boats in warm waters, I've seen it reduce the inner diameter of a 1.5" line to less than 1/2" in as little as a year. Repeated doses of undiluted white vinegaqr flushed ALL the way through to the tank--do NOT leave it sitting in the bowl!--will dissolve sea water calcium carbonates...a cupful flushed through once a week will prevent it.
A blocked tank vent will pressurized the tank, creating backpressure that'll cause a toilet to spit up. Check the vent thru-hull and the connection to the tank--both the fitting and that end of the vent line. If your joker valve was scale (sea water calcium carbonate) encrusted, it's a good bet that there's also enough buildup in the head discharge line to reduce the diameter enough to create back pressure that'll cause a toilet to "burp" or spit up. On boats in warm waters, I've seen it reduce the inner diameter of a 1.5" line to less than 1/2" in as little as a year. Repeated doses of undiluted white vinegaqr flushed ALL the way through to the tank--do NOT leave it sitting in the bowl!--will dissolve sea water calcium carbonates...a cupful flushed through once a week will prevent it.
Did you check/change the flapper valve?
If you pull the pump handle there is a square rubber valve that has an attached weight, it fits in the pipe/tube leading to the joker valve. I had a similar problem and everyone told me it was the joker valve, I happened to buy the complete overhaul kit and replaced everything, figured if I was there I might as well take care of everything....The weight on the square valve had come loose, not closing all the way and causing a little splash back.
If you pull the pump handle there is a square rubber valve that has an attached weight, it fits in the pipe/tube leading to the joker valve. I had a similar problem and everyone told me it was the joker valve, I happened to buy the complete overhaul kit and replaced everything, figured if I was there I might as well take care of everything....The weight on the square valve had come loose, not closing all the way and causing a little splash back.
Jabsco agrees with Peggy...
Rob and Peggy, thanks for the replies. I contacted Jabsco tech support and was told to use vinegar to clean the scaling. He also told me to check the vented loop and lines, but everything was clear. He told me to allow the vinegar to work overnight and then try again in the morning. (He also said to use vinegar regularly along with mineral oil.)After that, I'll move on to Rob's suggestion and post my results here. Peggy, I forgot to tell you that the other head in my boat works fine. Also, I pumped out the holding tank before doing any work today (in case either of these things matters, probably not). Thanks!
Rob and Peggy, thanks for the replies. I contacted Jabsco tech support and was told to use vinegar to clean the scaling. He also told me to check the vented loop and lines, but everything was clear. He told me to allow the vinegar to work overnight and then try again in the morning. (He also said to use vinegar regularly along with mineral oil.)After that, I'll move on to Rob's suggestion and post my results here. Peggy, I forgot to tell you that the other head in my boat works fine. Also, I pumped out the holding tank before doing any work today (in case either of these things matters, probably not). Thanks!
End result
The vinegar treatment worked. I poured a cupful into the bowl, then flushed through only a couple of strokes so as to let it penetrate in the pump assembly, not beyond. Head now flushes properly. I suspect that Rob was correct that the scale was hanging up the flapper valve (or something else). Will now use vinegar weekly per Jabsco recommendation. Also, the mineral oil (one capful, per Jabsco) really helped the pump to feel and operate smoothly. Thanks for the input.
The vinegar treatment worked. I poured a cupful into the bowl, then flushed through only a couple of strokes so as to let it penetrate in the pump assembly, not beyond. Head now flushes properly. I suspect that Rob was correct that the scale was hanging up the flapper valve (or something else). Will now use vinegar weekly per Jabsco recommendation. Also, the mineral oil (one capful, per Jabsco) really helped the pump to feel and operate smoothly. Thanks for the input.
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