Suddenly we have occasional air bubbles and waste flowing back into the toilet bowl. The lever for dry bowl or wet bowl still works perfect. I closed the thru hull just to make sure raw water wasn't siphoning in. No change. I suspected a spider clogged tank vent next. It was a bit restricted, but after correction-I still have the problem. I'm 100% comfortable dissembling and replacing what ever, but if anybody has had this ocurr and figured it out. I'd appreciate your tips. Thanks
Jabsco marine toilet backflowing from tank into bowl
- Thread starter Jimongee
- Start date
Air bubbles along with backflow are pretty good indication of blocked tank vent...especially if you're feeling ANY increase in resistance when you pump it. 99.99% of vent blockages occur in two places--the vent thru-hull and the connection to the tank--both that end of the vent line and the vent fitting in the tank. So start by using a screwdriver blade, ice pick or whatever works to scrape out the vent thru-hull. Then CAREFULLY open the deck pumpout cap to relieve any pressure in the system and remove the vent line from the tank...scrape those out. Don't use the toilet again till you've cleared the vent 'cuz flushing against a blocked vent pressurizes the system. Don't try to pump out either...'cuz a pump pulling against a blocked vent will pull a vacuum that prevents it from getting more than a gallon or two out. A particularly strong pumpout can even implode a tank.
As is true of most things, prevention is cheaper and easier than cure...So if you want to prevent future vent blockages, replace the "vent" thru-hull with an open bulkhead thru-hull--one you can stick your finger into. Every time you wash the boat and/or pump out, stick a hose nozzle up against it and back flush the vent line...sending any spiders who've tried to set up housekeeping in it or waste that's spilled into it when heeled on a nice water slide ride into the tank.
As is true of most things, prevention is cheaper and easier than cure...So if you want to prevent future vent blockages, replace the "vent" thru-hull with an open bulkhead thru-hull--one you can stick your finger into. Every time you wash the boat and/or pump out, stick a hose nozzle up against it and back flush the vent line...sending any spiders who've tried to set up housekeeping in it or waste that's spilled into it when heeled on a nice water slide ride into the tank.
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And then pick up a copy of my latest book, which is full of information about how to prevent problems instead of having to fix 'em...available from the sbo.com online store (see link in my signature).