My standard toilet is having a flushing problem. The first time it is flushed it will fill the bowl with water and slowly drain, never exchanging all the water. The next time it is flushed, it works "normally". There is a vigorous swirling action with the entire bowl emptying. It is not a dual flush model.
I have tried adjusting the tank water level and plunging the drain, but no difference.
Any help would be appreciated.
Dek