Hi! I’ve been researching all I can to solve my issue. I have a 1998 Carver 370 Vogayer with a Vacuflush system. After flushing the toilet, during its pumping cycle waste/poop comes out of the side vent. The tank looks like it’s empty to 1/4 full. I just purchased the boat and working through troubleshooting but hopefully someone here has some insight. I found out the hard way. Moored on a dock with people sitting next to our boat, flush, then waste all over the dock 2 feet away.

Any ideas on the root cause? I am thinking a clog of some sort ...