My toilet won't flush - it does what I call water exchange. I ran a hose down vent stack and it rinsed out as it should. Cleared all holes in bowl, put a rock in the tank. When it flushes, it fills bowl just below 3/4" of coming up and over bowl. It swirls but with little force. As tank begins to fill, bowl continues to fill.
I have always thought water level in toilet bowel was too high. It will flush when I use a bucket of water.
Side note: my house is set with a grinder and pump to get to city sewer - very slight slope, not noticeable. Checked flapper.