I have three toilets that all flush slowly and incompletely. I've adjusted the chain to ensure the flap raises completely. I've raised the float to ensure the tank fills nice and high. Yet I have this nagging issue on all my toilets. It often takes multiple flushes to clear simple waste and toilet paper, never mind the "hard" stuff.
All the sinks and tubs drain well, no issues. I'm wondering if the age of a toilet can be a factor. All of my toilets are from the mid-eighties. I'm getting to the point where I just want to replace thm with some water-saving toilets but it would suck to have the problem persist.