Help. About 4 weeks ago our downstairs toilet stopped flushing properly. We've tried to plunge it out and did not find anything. No reason to expect its clogged - I think. Also, when the toilet is first flushed air bubbles come out of the jet. I felt down into the bowl and the jet has some build up in it. I scraped out as much as I could. The water is swirling so I don't think it's an issue with the holes along the rim. The water swirls around OK but then slowly empties (as swirling)

Has anyone encountered something like this before? I assume the toilet is old because everything in this house is old. (if that affects anything)

Any advice or guidance you can give would be much appreciated. Thanks

Tell me more about the air bubbles that emerge from the jet hole. When do they occur? As the water comes down from the tank or after it's flushed and filling. Big or little bubbles? Lots of them or a few?
Back to you, Tom